diff --git a/caps/nsScriptSecurityManager.cpp b/caps/nsScriptSecurityManager.cpp
index 9979b9dfbcf1..54c86aaf030e 100644
--- a/caps/nsScriptSecurityManager.cpp
+++ b/caps/nsScriptSecurityManager.cpp
@@ -231,8 +231,8 @@ uint32_t nsScriptSecurityManager::SecurityHashURI(nsIURI* aURI) {
 
 bool nsScriptSecurityManager::IsHttpOrHttpsAndCrossOrigin(nsIURI* aUriA,
                                                           nsIURI* aUriB) {
-  if (!aUriA || (!net::SchemeIsHTTP(aUriA) && !net::SchemeIsHTTPS(aUriA)) ||
-      !aUriB || (!net::SchemeIsHTTP(aUriB) && !net::SchemeIsHTTPS(aUriB))) {
+  if (!aUriA || !net::SchemeIsHttpOrHttps(aUriA) || !aUriB ||
+      !net::SchemeIsHttpOrHttps(aUriB)) {
     return false;
   }
   if (!SecurityCompareURIs(aUriA, aUriB)) {
diff --git a/docshell/base/BrowsingContext.cpp b/docshell/base/BrowsingContext.cpp
index 2b94131e1f2f..b83a470f44ee 100644
--- a/docshell/base/BrowsingContext.cpp
+++ b/docshell/base/BrowsingContext.cpp
@@ -2040,7 +2040,7 @@ nsresult BrowsingContext::LoadURI(nsDocShellLoadState* aLoadState,
 
   const auto& sourceBC = aLoadState->SourceBrowsingContext();
 
-  if (net::SchemeIsJavascript(aLoadState->URI())) {
+  if (aLoadState->URI()->SchemeIs("javascript")) {
     if (!XRE_IsParentProcess()) {
       // Web content should only be able to load javascript: URIs into documents
       // whose principals the caller principal subsumes, which by definition
@@ -2135,7 +2135,7 @@ nsresult BrowsingContext::InternalLoad(nsDocShellLoadState* aLoadState) {
 
   const auto& sourceBC = aLoadState->SourceBrowsingContext();
 
-  if (net::SchemeIsJavascript(aLoadState->URI())) {
+  if (aLoadState->URI()->SchemeIs("javascript")) {
     if (!XRE_IsParentProcess()) {
       // Web content should only be able to load javascript: URIs into documents
       // whose principals the caller principal subsumes, which by definition
diff --git a/docshell/base/CanonicalBrowsingContext.cpp b/docshell/base/CanonicalBrowsingContext.cpp
index b817dcea0410..eb99262d3e8c 100644
--- a/docshell/base/CanonicalBrowsingContext.cpp
+++ b/docshell/base/CanonicalBrowsingContext.cpp
@@ -2398,18 +2398,18 @@ bool CanonicalBrowsingContext::SupportsLoadingInParent(
   // DocumentChannel currently only supports connecting channels into the
   // content process, so we can only support schemes that will always be loaded
   // there for now. Restrict to just http(s) for simplicity.
-  if (!net::SchemeIsHTTP(aLoadState->URI()) &&
-      !net::SchemeIsHTTPS(aLoadState->URI())) {
+  if (!net::SchemeIsHttpOrHttps(aLoadState->URI())) {
     return false;
   }
 
   if (WindowGlobalParent* global = GetCurrentWindowGlobal()) {
     nsCOMPtr<nsIURI> currentURI = global->GetDocumentURI();
     if (currentURI) {
+      nsCOMPtr<nsIURI> uri = aLoadState->URI();
       bool newURIHasRef = false;
-      aLoadState->URI()->GetHasRef(&newURIHasRef);
+      uri->GetHasRef(&newURIHasRef);
       bool equalsExceptRef = false;
-      aLoadState->URI()->EqualsExceptRef(currentURI, &equalsExceptRef);
+      uri->EqualsExceptRef(currentURI, &equalsExceptRef);
 
       if (equalsExceptRef && newURIHasRef) {
         // This navigation is same-doc WRT the current one, we should pass it
@@ -2454,7 +2454,7 @@ bool CanonicalBrowsingContext::LoadInParent(nsDocShellLoadState* aLoadState,
     return false;
   }
 
-  MOZ_ASSERT(!net::SchemeIsJavascript(aLoadState->URI()));
+  MOZ_ASSERT(!aLoadState->URI()->SchemeIs("javascript"));
 
   MOZ_ALWAYS_SUCCEEDS(
       SetParentInitiatedNavigationEpoch(++gParentInitiatedNavigationEpoch));
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index d6b51882f50b..bdeaa6e86c4f 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -667,7 +667,7 @@ nsDocShell::SetCancelContentJSEpoch(int32_t aEpoch) {
 
 nsresult nsDocShell::CheckDisallowedJavascriptLoad(
     nsDocShellLoadState* aLoadState) {
-  if (!net::SchemeIsJavascript(aLoadState->URI())) {
+  if (!aLoadState->URI()->SchemeIs("javascript")) {
     return NS_OK;
   }
 
@@ -1616,8 +1616,8 @@ nsDocShell::ForceEncodingDetection() {
 
   mForcedAutodetection = true;
 
-  nsIURI* url = doc->GetOriginalURI();
-  bool isFileURL = url && SchemeIsFile(url);
+  nsIURI* uri = doc->GetOriginalURI();
+  bool isFileURL = uri && uri->SchemeIs("file");
 
   int32_t charsetSource = doc->GetDocumentCharacterSetSource();
   auto encoding = doc->GetDocumentCharacterSet();
@@ -3710,7 +3710,7 @@ nsDocShell::DisplayLoadError(nsresult aError, nsIURI* aURI,
     if (aURI) {
       // displaying "file://" is aesthetically unpleasing and could even be
       // confusing to the user
-      if (SchemeIsFile(aURI)) {
+      if (aURI->SchemeIs("file")) {
         aURI->GetPathQueryRef(spec);
       } else {
         aURI->GetSpec(spec);
@@ -3740,7 +3740,7 @@ nsDocShell::DisplayLoadError(nsresult aError, nsIURI* aURI,
   NS_ENSURE_FALSE(messageStr.IsEmpty(), NS_ERROR_FAILURE);
 
   if ((NS_ERROR_NET_INTERRUPT == aError || NS_ERROR_NET_RESET == aError) &&
-      SchemeIsHTTPS(aURI)) {
+      aURI->SchemeIs("https")) {
     // Maybe TLS intolerant. Treat this as an SSL error.
     error = "nssFailure2";
   }
@@ -5780,7 +5780,7 @@ already_AddRefed<nsIURI> nsDocShell::MaybeFixBadCertDomainErrorURI(
   }
 
   // Return if scheme is not HTTPS.
-  if (!SchemeIsHTTPS(aUrl)) {
+  if (!aUrl->SchemeIs("https")) {
     return nullptr;
   }
 
@@ -5949,10 +5949,8 @@ already_AddRefed<nsIURI> nsDocShell::AttemptURIFixup(
     // Someone needs to clean up keywords in general so we can
     // determine on a per url basis if we want keywords
     // enabled...this is just a bandaid...
-    nsAutoCString scheme;
-    Unused << url->GetScheme(scheme);
     if (Preferences::GetBool("keyword.enabled", false) &&
-        StringBeginsWith(scheme, "http"_ns)) {
+        net::SchemeIsHttpOrHttps(url)) {
       bool attemptFixup = false;
       nsAutoCString host;
       Unused << url->GetHost(host);
@@ -6050,7 +6048,7 @@ already_AddRefed<nsIURI> nsDocShell::AttemptURIFixup(
   } else if (aStatus == NS_ERROR_CONNECTION_REFUSED &&
              Preferences::GetBool("browser.fixup.fallback-to-https", false)) {
     // Try HTTPS, since http didn't work
-    if (SchemeIsHTTP(url)) {
+    if (url->SchemeIs("http")) {
       int32_t port = 0;
       url->GetPort(&port);
 
@@ -9309,7 +9307,7 @@ nsresult nsDocShell::InternalLoad(nsDocShellLoadState* aLoadState,
     MOZ_DIAGNOSTIC_ASSERT(aLoadState->LoadType() == LOAD_NORMAL);
 
     // Disallow external chrome: loads targetted at content windows
-    if (SchemeIsChrome(aLoadState->URI())) {
+    if (aLoadState->URI()->SchemeIs("chrome")) {
       NS_WARNING("blocked external chrome: url -- use '--chrome' option");
       return NS_ERROR_FAILURE;
     }
@@ -9353,7 +9351,7 @@ nsresult nsDocShell::InternalLoad(nsDocShellLoadState* aLoadState,
 
   // XXXbz mTiming should know what channel it's for, so we don't
   // need this hackery.
-  const bool isJavaScript = SchemeIsJavascript(aLoadState->URI());
+  const bool isJavaScript = aLoadState->URI()->SchemeIs("javascript");
   const bool isExternalProtocol =
       nsContentUtils::IsExternalProtocol(aLoadState->URI());
   const bool isDownload = !aLoadState->FileName().IsVoid();
@@ -9733,7 +9731,7 @@ nsIPrincipal* nsDocShell::GetInheritedPrincipal(
         MOZ_ALWAYS_SUCCEEDS(vsc->SetBaseURI(aBaseURI));
       }
     }
-  } else if (SchemeIsViewSource(aURI)) {
+  } else if (aURI->SchemeIs("view-source")) {
     // Instantiate view source handler protocol, if it doesn't exist already.
     nsCOMPtr<nsIIOService> io(do_GetIOService());
     MOZ_ASSERT(io);
@@ -10239,7 +10237,7 @@ nsresult nsDocShell::DoURILoad(nsDocShellLoadState* aLoadState,
     while (nestedURI) {
       // view-source should always be an nsINestedURI, loop and check the
       // scheme on this and all inner URIs that are also nested URIs.
-      if (SchemeIsViewSource(tempURI)) {
+      if (tempURI->SchemeIs("view-source")) {
         return NS_ERROR_UNKNOWN_PROTOCOL;
       }
       nestedURI->GetInnerURI(getter_AddRefs(tempURI));
@@ -10256,20 +10254,21 @@ nsresult nsDocShell::DoURILoad(nsDocShellLoadState* aLoadState,
   //    configured as unique opaque origin.
   bool inheritPrincipal = false;
 
+  nsCOMPtr<nsIURI> uri = aLoadState->URI();
   if (aLoadState->PrincipalToInherit()) {
     bool isSrcdoc =
         aLoadState->HasInternalLoadFlags(INTERNAL_LOAD_FLAGS_IS_SRCDOC);
     bool inheritAttrs = nsContentUtils::ChannelShouldInheritPrincipal(
-        aLoadState->PrincipalToInherit(), aLoadState->URI(),
+        aLoadState->PrincipalToInherit(), uri,
         true,  // aInheritForAboutBlank
         isSrcdoc);
 
-    inheritPrincipal = inheritAttrs && !SchemeIsData(aLoadState->URI());
+    inheritPrincipal = inheritAttrs && !uri->SchemeIs("data");
   }
 
   // See https://bugzilla.mozilla.org/show_bug.cgi?id=1736570
   const bool isAboutBlankLoadOntoInitialAboutBlank =
-      IsAboutBlankLoadOntoInitialAboutBlank(aLoadState->URI(), inheritPrincipal,
+      IsAboutBlankLoadOntoInitialAboutBlank(uri, inheritPrincipal,
                                             aLoadState->PrincipalToInherit());
 
   // FIXME We still have a ton of codepaths that don't pass through
@@ -10282,7 +10281,7 @@ nsresult nsDocShell::DoURILoad(nsDocShellLoadState* aLoadState,
     // Materialize LoadingSessionHistoryInfo here, because DocumentChannel
     // loads have it, and later history behavior depends on it existing.
     UniquePtr<SessionHistoryInfo> entry = MakeUnique<SessionHistoryInfo>(
-        aLoadState->URI(), aLoadState->TriggeringPrincipal(),
+        uri, aLoadState->TriggeringPrincipal(),
         aLoadState->PrincipalToInherit(),
         aLoadState->PartitionedPrincipalToInherit(), aLoadState->Csp(),
         mContentTypeHint);
@@ -10394,8 +10393,7 @@ nsresult nsDocShell::DoURILoad(nsDocShellLoadState* aLoadState,
       aLoadState->GetLoadIdentifier());
   RefPtr<LoadInfo> loadInfo =
       (contentPolicyType == nsIContentPolicy::TYPE_DOCUMENT)
-          ? new LoadInfo(loadingWindow, aLoadState->URI(),
-                         aLoadState->TriggeringPrincipal(),
+          ? new LoadInfo(loadingWindow, uri, aLoadState->TriggeringPrincipal(),
                          topLevelLoadingContext, securityFlags, sandboxFlags)
           : new LoadInfo(loadingPrincipal, aLoadState->TriggeringPrincipal(),
                          loadingNode, securityFlags, contentPolicyType,
@@ -10502,7 +10500,7 @@ nsresult nsDocShell::DoURILoad(nsDocShellLoadState* aLoadState,
       mBrowsingContext, uriModified, Some(isEmbeddingBlockedError));
 
   nsCOMPtr<nsIChannel> channel;
-  if (DocumentChannel::CanUseDocumentChannel(aLoadState->URI()) &&
+  if (DocumentChannel::CanUseDocumentChannel(uri) &&
       !isAboutBlankLoadOntoInitialAboutBlank) {
     channel = DocumentChannel::CreateForDocument(
         aLoadState, loadInfo, loadFlags, this, cacheKey, uriModified,
@@ -12065,7 +12063,7 @@ nsresult nsDocShell::LoadHistoryEntry(nsDocShellLoadState* aLoadState,
   aLoadState->SetLoadType(aLoadType);
 
   nsresult rv;
-  if (SchemeIsJavascript(aLoadState->URI())) {
+  if (aLoadState->URI()->SchemeIs("javascript")) {
     // We're loading a URL that will execute script from inside asyncOpen.
     // Replace the current document with about:blank now to prevent
     // anything from the current document from leaking into any JavaScript
@@ -12908,7 +12906,7 @@ nsresult nsDocShell::OnLinkClick(
 bool nsDocShell::ShouldOpenInBlankTarget(const nsAString& aOriginalTarget,
                                          nsIURI* aLinkURI, nsIContent* aContent,
                                          bool aIsUserTriggered) {
-  if (net::SchemeIsJavascript(aLinkURI)) {
+  if (aLinkURI->SchemeIs("javascript")) {
     return false;
   }
 
diff --git a/docshell/base/nsPingListener.cpp b/docshell/base/nsPingListener.cpp
index bcf43cfdad14..7355ff83010b 100644
--- a/docshell/base/nsPingListener.cpp
+++ b/docshell/base/nsPingListener.cpp
@@ -278,7 +278,7 @@ static void ForEachPing(nsIContent* aContent, ForEachPingCallback aCallback,
       continue;
     }
     // Explicitly not allow loading data: URIs
-    if (!net::SchemeIsData(uri)) {
+    if (!uri->SchemeIs("data")) {
       aCallback(aClosure, aContent, uri, ios);
     }
   }
diff --git a/dom/base/EventSource.cpp b/dom/base/EventSource.cpp
index 71d6ee74f71e..67d2ed8bb216 100644
--- a/dom/base/EventSource.cpp
+++ b/dom/base/EventSource.cpp
@@ -826,7 +826,7 @@ EventSourceImpl::AsyncOnChannelRedirect(
   rv = NS_GetFinalChannelURI(aNewChannel, getter_AddRefs(newURI));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  bool isValidScheme = newURI->SchemeIs("http") || newURI->SchemeIs("https");
+  bool isValidScheme = net::SchemeIsHttpOrHttps(newURI);
 
   rv =
       mIsMainThread ? GetEventSource()->CheckCurrentGlobalCorrectness() : NS_OK;
@@ -988,7 +988,7 @@ nsresult EventSourceImpl::InitChannelAndRequestEventSource(
     return NS_ERROR_ABORT;
   }
 
-  bool isValidScheme = mSrc->SchemeIs("http") || mSrc->SchemeIs("https");
+  bool isValidScheme = net::SchemeIsHttpOrHttps(mSrc);
 
   MOZ_ASSERT_IF(mIsMainThread, aEventTargetAccessAllowed);
 
diff --git a/dom/base/Location.cpp b/dom/base/Location.cpp
index fbf9b188e4f7..33902b2b23d3 100644
--- a/dom/base/Location.cpp
+++ b/dom/base/Location.cpp
@@ -456,7 +456,7 @@ void Location::SetProtocol(const nsACString& aProtocol,
     return;
   }
 
-  if (!uri->SchemeIs("http") && !uri->SchemeIs("https")) {
+  if (!net::SchemeIsHttpOrHttps(uri)) {
     // No-op, per spec.
     return;
   }
diff --git a/dom/base/LocationBase.cpp b/dom/base/LocationBase.cpp
index 443065dca835..489e368f76af 100644
--- a/dom/base/LocationBase.cpp
+++ b/dom/base/LocationBase.cpp
@@ -162,7 +162,7 @@ void LocationBase::SetURI(nsIURI* aURI, nsIPrincipal& aSubjectPrincipal,
   rv = bc->LoadURI(loadState);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     if (rv == NS_ERROR_DOM_BAD_CROSS_ORIGIN_URI &&
-        net::SchemeIsJavascript(loadState->URI())) {
+        loadState->URI()->SchemeIs("javascript")) {
       // Per spec[1], attempting to load a javascript: URI into a cross-origin
       // BrowsingContext is a no-op, and should not raise an exception.
       // Technically, Location setters run with exceptions enabled should only
diff --git a/dom/base/Navigator.cpp b/dom/base/Navigator.cpp
index 5b0a6e787539..74be83180547 100644
--- a/dom/base/Navigator.cpp
+++ b/dom/base/Navigator.cpp
@@ -1236,7 +1236,7 @@ bool Navigator::SendBeaconInternal(const nsAString& aUrl,
   }
 
   // Spec disallows any schemes save for HTTP/HTTPs
-  if (!uri->SchemeIs("http") && !uri->SchemeIs("https")) {
+  if (!net::SchemeIsHttpOrHttps(uri)) {
     aRv.ThrowTypeError<MSG_INVALID_URL_SCHEME>("Beacon",
                                                uri->GetSpecOrDefault());
     return false;
diff --git a/dom/base/ThirdPartyUtil.cpp b/dom/base/ThirdPartyUtil.cpp
index 5b24bda438a1..1a46ad53cb5e 100644
--- a/dom/base/ThirdPartyUtil.cpp
+++ b/dom/base/ThirdPartyUtil.cpp
@@ -455,7 +455,7 @@ ThirdPartyUtil::GetBaseDomain(nsIURI* aHostURI, nsACString& aBaseDomain) {
 
     // The aHostURI can be a view-source URI, in which case we need to get the
     // base domain from the inner most URI.
-    if (net::SchemeIsViewSource(aHostURI)) {
+    if (aHostURI->SchemeIs("view-source")) {
       rv = NS_GetInnermostURIHost(aHostURI, aBaseDomain);
     } else {
       rv = aHostURI->GetAsciiHost(aBaseDomain);
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index e95034d76548..50d18cd5752d 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -7113,8 +7113,8 @@ nsresult nsContentUtils::GetWebExposedOriginSerialization(nsIURI* aURI,
 
     if (
         // Schemes in spec. https://url.spec.whatwg.org/#origin
-        !uri->SchemeIs("http") && !uri->SchemeIs("https") &&
-        !uri->SchemeIs("file") && !uri->SchemeIs("resource") &&
+        !net::SchemeIsHttpOrHttps(uri) && !uri->SchemeIs("file") &&
+        !uri->SchemeIs("resource") &&
         // Our own schemes.
         !uri->SchemeIs("moz-extension")) {
       aOrigin.AssignLiteral("null");
diff --git a/dom/base/nsObjectLoadingContent.cpp b/dom/base/nsObjectLoadingContent.cpp
index 4b7e309de0d3..5b72a13863a5 100644
--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -1402,7 +1402,7 @@ nsresult nsObjectLoadingContent::OpenChannel() {
       true,                 // aInheritForAboutBlank
       false);               // aForceInherit
 
-  bool inheritPrincipal = inheritAttrs && !SchemeIsData(mURI);
+  bool inheritPrincipal = inheritAttrs && !mURI->SchemeIs("data");
 
   nsSecurityFlags securityFlags =
       nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL;
diff --git a/dom/events/IMEStateManager.cpp b/dom/events/IMEStateManager.cpp
index 86e3725b4cc5..77a6ccb01eca 100644
--- a/dom/events/IMEStateManager.cpp
+++ b/dom/events/IMEStateManager.cpp
@@ -1962,7 +1962,7 @@ void IMEStateManager::SetIMEState(const IMEState& aState,
       //       other apps like IME know which one is touched by the user because
       //       malicious text services may like files which are explicitly used
       //       by the user better.
-      if (uri->SchemeIs("http") || uri->SchemeIs("https")) {
+      if (net::SchemeIsHttpOrHttps(uri)) {
         // Note that we don't need to expose UserPass, Query and Reference to
         // IME since they may contain sensitive data, but non-malicious text
         // services must not require these data.
diff --git a/dom/ipc/BrowserChild.cpp b/dom/ipc/BrowserChild.cpp
index 93f20a36acef..24b950350a1f 100644
--- a/dom/ipc/BrowserChild.cpp
+++ b/dom/ipc/BrowserChild.cpp
@@ -3550,8 +3550,7 @@ nsresult BrowserChild::CanCancelContentJS(
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsCOMPtr<nsIURI> currentURI = entry->GetURI();
-  if (!currentURI->SchemeIs("http") && !currentURI->SchemeIs("https") &&
-      !currentURI->SchemeIs("file")) {
+  if (!net::SchemeIsHttpOrHttps(currentURI) && !currentURI->SchemeIs("file")) {
     // Only cancel content JS for http(s) and file URIs. Other URIs are probably
     // internal and we should just let them run to completion.
     return NS_OK;
diff --git a/dom/ipc/BrowserParent.cpp b/dom/ipc/BrowserParent.cpp
index 3ebb9f420d0d..25137bea3b6e 100644
--- a/dom/ipc/BrowserParent.cpp
+++ b/dom/ipc/BrowserParent.cpp
@@ -3746,8 +3746,7 @@ bool BrowserParent::CanCancelContentJS(
                     false);
 
   nsCOMPtr<nsIURI> currentURI = entry->GetURI();
-  if (!currentURI->SchemeIs("http") && !currentURI->SchemeIs("https") &&
-      !currentURI->SchemeIs("file")) {
+  if (!net::SchemeIsHttpOrHttps(currentURI) && !currentURI->SchemeIs("file")) {
     // Only cancel content JS for http(s) and file URIs. Other URIs are probably
     // internal and we should just let them run to completion.
     return false;
diff --git a/dom/ipc/WindowGlobalParent.cpp b/dom/ipc/WindowGlobalParent.cpp
index 9c386c4665d5..63055ad953d2 100644
--- a/dom/ipc/WindowGlobalParent.cpp
+++ b/dom/ipc/WindowGlobalParent.cpp
@@ -332,7 +332,7 @@ mozilla::ipc::IPCResult WindowGlobalParent::RecvLoadURI(
     return IPC_OK();
   }
 
-  if (net::SchemeIsJavascript(aLoadState->URI())) {
+  if (aLoadState->URI()->SchemeIs("javascript")) {
     return IPC_FAIL(this, "Illegal cross-process javascript: load attempt");
   }
 
@@ -365,7 +365,7 @@ mozilla::ipc::IPCResult WindowGlobalParent::RecvInternalLoad(
     return IPC_OK();
   }
 
-  if (net::SchemeIsJavascript(aLoadState->URI())) {
+  if (aLoadState->URI()->SchemeIs("javascript")) {
     return IPC_FAIL(this, "Illegal cross-process javascript: load attempt");
   }
 
@@ -1372,23 +1372,23 @@ mozilla::ipc::IPCResult WindowGlobalParent::RecvSetDocumentDomain(
 
 mozilla::ipc::IPCResult WindowGlobalParent::RecvReloadWithHttpsOnlyException() {
   nsresult rv;
-  nsCOMPtr<nsIURI> currentUri = BrowsingContext()->Top()->GetCurrentURI();
+  nsCOMPtr<nsIURI> currentURI = BrowsingContext()->Top()->GetCurrentURI();
 
-  if (!currentUri) {
+  if (!currentURI) {
     return IPC_FAIL(this, "HTTPS-only mode: Failed to get current URI");
   }
 
-  bool isViewSource = currentUri->SchemeIs("view-source");
+  bool isViewSource = currentURI->SchemeIs("view-source");
 
-  nsCOMPtr<nsINestedURI> nestedURI = do_QueryInterface(currentUri);
+  nsCOMPtr<nsINestedURI> nestedURI = do_QueryInterface(currentURI);
   nsCOMPtr<nsIURI> innerURI;
   if (isViewSource) {
     nestedURI->GetInnerURI(getter_AddRefs(innerURI));
   } else {
-    innerURI = currentUri;
+    innerURI = currentURI;
   }
 
-  if (!innerURI->SchemeIs("https") && !innerURI->SchemeIs("http")) {
+  if (!net::SchemeIsHttpOrHttps(innerURI)) {
     return IPC_FAIL(this, "HTTPS-only mode: Illegal state");
   }
 
@@ -1641,8 +1641,7 @@ void WindowGlobalParent::ActorDestroy(ActorDestroyReason aWhy) {
           BrowsingContext()->IsTopContent()) {
         GetContentBlockingLog()->ReportLog();
 
-        if (mDocumentURI && (net::SchemeIsHTTP(mDocumentURI) ||
-                             net::SchemeIsHTTPS(mDocumentURI))) {
+        if (mDocumentURI && net::SchemeIsHttpOrHttps(mDocumentURI)) {
           GetContentBlockingLog()->ReportCanvasFingerprintingLog(
               DocumentPrincipal());
           GetContentBlockingLog()->ReportFontFingerprintingLog(
diff --git a/dom/prototype/PrototypeDocumentContentSink.cpp b/dom/prototype/PrototypeDocumentContentSink.cpp
index 6795937eaa2c..690ac03d80de 100644
--- a/dom/prototype/PrototypeDocumentContentSink.cpp
+++ b/dom/prototype/PrototypeDocumentContentSink.cpp
@@ -8,7 +8,6 @@
 #include "mozilla/dom/PrototypeDocumentContentSink.h"
 #include "nsIParser.h"
 #include "mozilla/dom/Document.h"
-#include "mozilla/dom/URL.h"
 #include "nsIContent.h"
 #include "nsIURI.h"
 #include "nsNetUtil.h"
@@ -666,7 +665,7 @@ nsresult PrototypeDocumentContentSink::DoneWalking() {
 
   StartLayout();
 
-  if (IsChromeURI(mDocumentURI) &&
+  if (mDocumentURI->SchemeIs("chrome") &&
       nsXULPrototypeCache::GetInstance()->IsEnabled()) {
     bool isCachedOnDisk;
     nsXULPrototypeCache::GetInstance()->HasPrototype(mDocumentURI,
@@ -733,7 +732,7 @@ nsresult PrototypeDocumentContentSink::LoadScript(
   // Load a transcluded script
   nsresult rv;
 
-  bool isChromeDoc = IsChromeURI(mDocumentURI);
+  bool isChromeDoc = mDocumentURI->SchemeIs("chrome");
 
   if (isChromeDoc && aScriptProto->HasStencil()) {
     rv = ExecuteScript(aScriptProto);
@@ -938,7 +937,8 @@ PrototypeDocumentContentSink::OnScriptCompileComplete(JS::Stencil* aStencil,
     // the true crime story.)
     bool useXULCache = nsXULPrototypeCache::GetInstance()->IsEnabled();
 
-    if (useXULCache && IsChromeURI(mDocumentURI) && scriptProto->HasStencil()) {
+    if (useXULCache && mDocumentURI->SchemeIs("chrome") &&
+        scriptProto->HasStencil()) {
       nsXULPrototypeCache::GetInstance()->PutStencil(scriptProto->mSrcURI,
                                                      scriptProto->GetStencil());
     }
diff --git a/dom/security/nsCSPContext.cpp b/dom/security/nsCSPContext.cpp
index ff5db2020dc7..bf974a1c9369 100644
--- a/dom/security/nsCSPContext.cpp
+++ b/dom/security/nsCSPContext.cpp
@@ -1005,10 +1005,9 @@ void StripURIForReporting(nsIURI* aSelfURI, nsIURI* aURI,
   // If the origin of aURI is a globally unique identifier (for example,
   // aURI has a scheme of data, blob, or filesystem), then
   // return the ASCII serialization of uri’s scheme.
-  bool isHttpOrWs = (aURI->SchemeIs("http") || aURI->SchemeIs("https") ||
-                     aURI->SchemeIs("ws") || aURI->SchemeIs("wss"));
+  bool isWsOrWss = aURI->SchemeIs("ws") || aURI->SchemeIs("wss");
 
-  if (!isHttpOrWs) {
+  if (!net::SchemeIsHttpOrHttps(aURI) && !isWsOrWss) {
     // not strictly spec compliant, but what we really care about is
     // http/https. If it's not http/https, then treat aURI
     // as if it's a globally unique identifier and just return the scheme.
@@ -1337,10 +1336,7 @@ nsresult nsCSPContext::SendReportsToURIs(
     }
 
     // log a warning to console if scheme is not http or https
-    bool isHttpScheme =
-        reportURI->SchemeIs("http") || reportURI->SchemeIs("https");
-
-    if (!isHttpScheme) {
+    if (!net::SchemeIsHttpOrHttps(reportURI)) {
       AutoTArray<nsString, 1> params = {reportURIs[r]};
       logToConsole("reportURInotHttpsOrHttp2", params,
                    NS_ConvertUTF16toUTF8(aViolationEventInit.mSourceFile),
diff --git a/dom/security/nsContentSecurityManager.cpp b/dom/security/nsContentSecurityManager.cpp
index fd84d6508f2b..ba21fe151caa 100644
--- a/dom/security/nsContentSecurityManager.cpp
+++ b/dom/security/nsContentSecurityManager.cpp
@@ -98,8 +98,7 @@ bool nsContentSecurityManager::AllowTopLevelNavigationToDataURI(
   nsCOMPtr<nsIURI> uri;
   nsresult rv = NS_GetFinalChannelURI(aChannel, getter_AddRefs(uri));
   NS_ENSURE_SUCCESS(rv, true);
-  bool isDataURI = uri->SchemeIs("data");
-  if (!isDataURI) {
+  if (!uri->SchemeIs("data")) {
     return true;
   }
 
@@ -175,11 +174,7 @@ bool nsContentSecurityManager::AllowInsecureRedirectToDataURI(
   }
   nsCOMPtr<nsIURI> newURI;
   nsresult rv = NS_GetFinalChannelURI(aNewChannel, getter_AddRefs(newURI));
-  if (NS_FAILED(rv) || !newURI) {
-    return true;
-  }
-  bool isDataURI = newURI->SchemeIs("data");
-  if (!isDataURI) {
+  if (NS_FAILED(rv) || !newURI || !newURI->SchemeIs("data")) {
     return true;
   }
 
@@ -1007,15 +1002,15 @@ nsresult nsContentSecurityManager::CheckAllowLoadInSystemPrivilegedContext(
 
   if (contentPolicyType == ExtContentPolicy::TYPE_SUBDOCUMENT) {
     if (StaticPrefs::security_disallow_privileged_https_subdocuments_loads() &&
-        (innerURI->SchemeIs("http") || innerURI->SchemeIs("https"))) {
+        net::SchemeIsHttpOrHttps(innerURI)) {
       MOZ_ASSERT(
           false,
           "Disallowing SystemPrincipal load of subdocuments on HTTP(S).");
       aChannel->Cancel(NS_ERROR_CONTENT_BLOCKED);
       return NS_ERROR_CONTENT_BLOCKED;
     }
-    if ((StaticPrefs::security_disallow_privileged_data_subdocuments_loads()) &&
-        (innerURI->SchemeIs("data"))) {
+    if (StaticPrefs::security_disallow_privileged_data_subdocuments_loads() &&
+        innerURI->SchemeIs("data")) {
       MOZ_ASSERT(
           false,
           "Disallowing SystemPrincipal load of subdocuments on data URL.");
@@ -1024,8 +1019,8 @@ nsresult nsContentSecurityManager::CheckAllowLoadInSystemPrivilegedContext(
     }
   }
   if (contentPolicyType == ExtContentPolicy::TYPE_SCRIPT) {
-    if ((StaticPrefs::security_disallow_privileged_https_script_loads()) &&
-        (innerURI->SchemeIs("http") || innerURI->SchemeIs("https"))) {
+    if (StaticPrefs::security_disallow_privileged_https_script_loads() &&
+        net::SchemeIsHttpOrHttps(innerURI)) {
       MOZ_ASSERT(false,
                  "Disallowing SystemPrincipal load of scripts on HTTP(S).");
       aChannel->Cancel(NS_ERROR_CONTENT_BLOCKED);
@@ -1034,7 +1029,7 @@ nsresult nsContentSecurityManager::CheckAllowLoadInSystemPrivilegedContext(
   }
   if (contentPolicyType == ExtContentPolicy::TYPE_STYLESHEET) {
     if (StaticPrefs::security_disallow_privileged_https_stylesheet_loads() &&
-        (innerURI->SchemeIs("http") || innerURI->SchemeIs("https"))) {
+        net::SchemeIsHttpOrHttps(innerURI)) {
       MOZ_ASSERT(false,
                  "Disallowing SystemPrincipal load of stylesheets on HTTP(S).");
       aChannel->Cancel(NS_ERROR_CONTENT_BLOCKED);
@@ -1091,8 +1086,7 @@ nsresult nsContentSecurityManager::CheckAllowLoadInPrivilegedAboutContext(
                       &isLocal);
   // We allow URLs that are URI_IS_LOCAL (but that includes `data`
   // and `blob` which are also undesirable.
-  if ((isLocal) && (!innerURI->SchemeIs("data")) &&
-      (!innerURI->SchemeIs("blob"))) {
+  if (isLocal && !innerURI->SchemeIs("data") && !innerURI->SchemeIs("blob")) {
     return NS_OK;
   }
   MOZ_ASSERT(
@@ -1759,10 +1753,8 @@ nsresult nsContentSecurityManager::CheckForIncoherentResultPrincipal(
 
   if (nsScriptSecurityManager::IsHttpOrHttpsAndCrossOrigin(
           resultSiteOriginURI, channelSiteOriginURI) ||
-      (!net::SchemeIsHTTP(resultSiteOriginURI) &&
-       !net::SchemeIsHTTPS(resultSiteOriginURI) &&
-       (net::SchemeIsHTTP(channelSiteOriginURI) ||
-        net::SchemeIsHTTPS(channelSiteOriginURI)))) {
+      (!net::SchemeIsHttpOrHttps(resultSiteOriginURI) &&
+       net::SchemeIsHttpOrHttps(channelSiteOriginURI))) {
     return NS_ERROR_CONTENT_BLOCKED;
   }
 
diff --git a/dom/security/nsHTTPSOnlyUtils.cpp b/dom/security/nsHTTPSOnlyUtils.cpp
index c4c9a0b20304..334b28d4ae51 100644
--- a/dom/security/nsHTTPSOnlyUtils.cpp
+++ b/dom/security/nsHTTPSOnlyUtils.cpp
@@ -927,12 +927,12 @@ bool nsHTTPSOnlyUtils::IsHttpDowngrade(nsIURI* aFromURI, nsIURI* aToURI) {
   }
 
   // 2. If the target URI is not http, then it's not a http downgrade
-  if (!mozilla::net::SchemeIsHTTP(aToURI)) {
+  if (!aToURI->SchemeIs("http")) {
     return false;
   }
 
   // 3. If the origin URI isn't https, then it's not a http downgrade either.
-  if (!mozilla::net::SchemeIsHTTPS(aFromURI)) {
+  if (!aFromURI->SchemeIs("https")) {
     return false;
   }
 
diff --git a/dom/serviceworkers/ServiceWorkerUtils.cpp b/dom/serviceworkers/ServiceWorkerUtils.cpp
index 8fd76dedccaf..3a290eae9eb2 100644
--- a/dom/serviceworkers/ServiceWorkerUtils.cpp
+++ b/dom/serviceworkers/ServiceWorkerUtils.cpp
@@ -236,7 +236,7 @@ void ServiceWorkerScopeAndScriptAreValid(const ClientInfo& aClientInfo,
   }
 
   auto hasHTTPScheme = [](nsIURI* aURI) -> bool {
-    return aURI->SchemeIs("http") || aURI->SchemeIs("https");
+    return net::SchemeIsHttpOrHttps(aURI);
   };
   auto hasMozExtScheme = [](nsIURI* aURI) -> bool {
     return aURI->SchemeIs("moz-extension");
diff --git a/dom/url/URL.cpp b/dom/url/URL.cpp
index eceaf9247258..6538fc62579b 100644
--- a/dom/url/URL.cpp
+++ b/dom/url/URL.cpp
@@ -153,8 +153,6 @@ URLSearchParams* URL::SearchParams() {
   return mSearchParams;
 }
 
-bool IsChromeURI(nsIURI* aURI) { return aURI->SchemeIs("chrome"); }
-
 void URL::CreateSearchParamsIfNeeded() {
   if (!mSearchParams) {
     mSearchParams = new URLSearchParams(mParent, this);
diff --git a/dom/url/URL.h b/dom/url/URL.h
index 7cf0deb23c0e..fb5b6b1366f4 100644
--- a/dom/url/URL.h
+++ b/dom/url/URL.h
@@ -135,8 +135,6 @@ class URL final : public URLSearchParamsObserver, public nsWrapperCache {
   nsCOMPtr<nsIURI> mURI;
 };
 
-bool IsChromeURI(nsIURI* aURI);
-
 }  // namespace dom
 }  // namespace mozilla
 
diff --git a/image/ImageBlocker.cpp b/image/ImageBlocker.cpp
index c8ff1baaafb0..67735e4cbaf9 100644
--- a/image/ImageBlocker.cpp
+++ b/image/ImageBlocker.cpp
@@ -58,6 +58,5 @@ bool ImageBlocker::ShouldBlock(nsIURI* aContentLocation) {
 
   // we only want to check http, https
   // for chrome:// and resources and others, no need to check.
-  return aContentLocation->SchemeIs("http") ||
-         aContentLocation->SchemeIs("https");
+  return net::SchemeIsHttpOrHttps(aContentLocation);
 }
diff --git a/intl/hyphenation/glue/nsHyphenator.cpp b/intl/hyphenation/glue/nsHyphenator.cpp
index 96faea1a816e..8a4c0b28e5c4 100644
--- a/intl/hyphenation/glue/nsHyphenator.cpp
+++ b/intl/hyphenation/glue/nsHyphenator.cpp
@@ -260,7 +260,7 @@ nsHyphenator::nsHyphenator(nsIURI* aURI, bool aHyphenateCapitalized)
   // We get file:// URIs when running an unpackaged build; they could also
   // occur if we support adding hyphenation dictionaries by putting files in
   // a directory of the profile, for example.
-  if (net::SchemeIsFile(aURI)) {
+  if (aURI->SchemeIs("file")) {
     // Ask the Rust lib to mmap the file. In this case our mDictSize field
     // remains zero; mDict is not a pointer to the raw data but an opaque
     // reference to a Rust object, and can only be freed by passing it to
diff --git a/netwerk/base/Predictor.cpp b/netwerk/base/Predictor.cpp
index 9752efe9201f..3ee7cc5ffc29 100644
--- a/netwerk/base/Predictor.cpp
+++ b/netwerk/base/Predictor.cpp
@@ -109,7 +109,7 @@ static bool IsNullOrHttp(nsIURI* uri) {
     return true;
   }
 
-  return uri->SchemeIs("http") || uri->SchemeIs("https");
+  return SchemeIsHttpOrHttps(uri);
 }
 
 // Listener for the speculative DNS requests we'll fire off, which just ignores
diff --git a/netwerk/base/nsIOService.cpp b/netwerk/base/nsIOService.cpp
index 4adc5f388879..e957628acc2f 100644
--- a/netwerk/base/nsIOService.cpp
+++ b/netwerk/base/nsIOService.cpp
@@ -2114,7 +2114,7 @@ nsresult nsIOService::SpeculativeConnectInternal(
     nsIInterfaceRequestor* aCallbacks, bool aAnonymous) {
   NS_ENSURE_ARG(aURI);
 
-  if (!aURI->SchemeIs("http") && !aURI->SchemeIs("https")) {
+  if (!SchemeIsHttpOrHttps(aURI)) {
     // We don't speculatively connect to non-HTTP[S] URIs.
     return NS_OK;
   }
diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
index 4d0767a8eab0..5ce40403fd0e 100644
--- a/netwerk/base/nsNetUtil.cpp
+++ b/netwerk/base/nsNetUtil.cpp
@@ -3366,59 +3366,9 @@ bool ChannelIsPost(nsIChannel* aChannel) {
   return false;
 }
 
-bool SchemeIsHTTP(nsIURI* aURI) {
+bool SchemeIsHttpOrHttps(nsIURI* aURI) {
   MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("http");
-}
-
-bool SchemeIsHTTPS(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("https");
-}
-
-bool SchemeIsJavascript(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("javascript");
-}
-
-bool SchemeIsChrome(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("chrome");
-}
-
-bool SchemeIsAbout(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("about");
-}
-
-bool SchemeIsBlob(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("blob");
-}
-
-bool SchemeIsFile(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("file");
-}
-
-bool SchemeIsData(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("data");
-}
-
-bool SchemeIsViewSource(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("view-source");
-}
-
-bool SchemeIsResource(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("resource");
-}
-
-bool SchemeIsFTP(nsIURI* aURI) {
-  MOZ_ASSERT(aURI);
-  return aURI->SchemeIs("ftp");
+  return aURI->SchemeIs("http") || aURI->SchemeIs("https");
 }
 
 bool SchemeIsSpecial(const nsACString& aScheme) {
diff --git a/netwerk/base/nsNetUtil.h b/netwerk/base/nsNetUtil.h
index b62fe5ea8f7a..6fbd162f2d0b 100644
--- a/netwerk/base/nsNetUtil.h
+++ b/netwerk/base/nsNetUtil.h
@@ -1091,21 +1091,9 @@ nsresult GetParameterHTTP(const nsACString& aHeaderVal, const char* aParamName,
 bool ChannelIsPost(nsIChannel* aChannel);
 
 /**
- * Convenience functions for verifying nsIURI schemes. These functions simply
- * wrap aURI->SchemeIs(), but specify the protocol as part of the function name.
+ * Convenience function for verifying nsIURI scheme is either HTTP or HTTPS.
  */
-
-bool SchemeIsHTTP(nsIURI* aURI);
-bool SchemeIsHTTPS(nsIURI* aURI);
-bool SchemeIsJavascript(nsIURI* aURI);
-bool SchemeIsChrome(nsIURI* aURI);
-bool SchemeIsAbout(nsIURI* aURI);
-bool SchemeIsBlob(nsIURI* aURI);
-bool SchemeIsFile(nsIURI* aURI);
-bool SchemeIsData(nsIURI* aURI);
-bool SchemeIsViewSource(nsIURI* aURI);
-bool SchemeIsResource(nsIURI* aURI);
-bool SchemeIsFTP(nsIURI* aURI);
+bool SchemeIsHttpOrHttps(nsIURI* aURI);
 
 // Helper functions for SetProtocol methods to follow
 // step 2.1 in https://url.spec.whatwg.org/#scheme-state
diff --git a/netwerk/ipc/DocumentChannel.cpp b/netwerk/ipc/DocumentChannel.cpp
index 0e8a9e02da88..9e33ce45cb11 100644
--- a/netwerk/ipc/DocumentChannel.cpp
+++ b/netwerk/ipc/DocumentChannel.cpp
@@ -156,7 +156,7 @@ nsDocShell* DocumentChannel::GetDocShell() {
 }
 
 static bool URIUsesDocChannel(nsIURI* aURI) {
-  if (SchemeIsJavascript(aURI)) {
+  if (aURI->SchemeIs("javascript")) {
     return false;
   }
 
diff --git a/netwerk/ipc/DocumentLoadListener.cpp b/netwerk/ipc/DocumentLoadListener.cpp
index 828e9c09dfc8..ec94730fe706 100644
--- a/netwerk/ipc/DocumentLoadListener.cpp
+++ b/netwerk/ipc/DocumentLoadListener.cpp
@@ -119,15 +119,15 @@ static auto SecurityFlagsForLoadInfo(nsDocShellLoadState* aLoadState)
   }
 
   if (aLoadState->PrincipalToInherit()) {
+    nsIURI* uri = aLoadState->URI();
     bool isSrcdoc = aLoadState->HasInternalLoadFlags(
         nsDocShell::INTERNAL_LOAD_FLAGS_IS_SRCDOC);
     bool inheritAttrs = nsContentUtils::ChannelShouldInheritPrincipal(
-        aLoadState->PrincipalToInherit(), aLoadState->URI(),
+        aLoadState->PrincipalToInherit(), uri,
         true,  // aInheritForAboutBlank
         isSrcdoc);
 
-    bool isData = SchemeIsData(aLoadState->URI());
-    if (inheritAttrs && !isData) {
+    if (inheritAttrs && !uri->SchemeIs("data")) {
       securityFlags |= nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL;
     }
   }
@@ -691,7 +691,7 @@ auto DocumentLoadListener::Open(nsDocShellLoadState* aLoadState,
   mLoadIdentifier = aLoadState->GetLoadIdentifier();
   // See description of  mFileName in nsDocShellLoadState.h
   mIsDownload = !aLoadState->FileName().IsVoid();
-  mIsLoadingJSURI = net::SchemeIsJavascript(aLoadState->URI());
+  mIsLoadingJSURI = aLoadState->URI()->SchemeIs("javascript");
   mHTTPSFirstDowngradeData = aLoadState->GetHttpsFirstDowngradeData().forget();
 
   // Check for infinite recursive object or iframe loads
diff --git a/netwerk/protocol/http/HttpBaseChannel.cpp b/netwerk/protocol/http/HttpBaseChannel.cpp
index 0b2ac14fdef3..9b95b14bddeb 100644
--- a/netwerk/protocol/http/HttpBaseChannel.cpp
+++ b/netwerk/protocol/http/HttpBaseChannel.cpp
@@ -4473,7 +4473,7 @@ already_AddRefed<nsILoadInfo> HttpBaseChannel::CloneLoadInfoForRedirect(
     // the "external" flag, as loads that now go to other apps should be
     // allowed to go ahead and not trip infinite-loop protection
     // (see bug 1717314 for context).
-    if (!aNewURI->SchemeIs("http") && !aNewURI->SchemeIs("https")) {
+    if (!net::SchemeIsHttpOrHttps(aNewURI)) {
       newLoadInfo->SetLoadTriggeredFromExternal(false);
     }
     newLoadInfo->ResetSandboxedNullPrincipalID();
diff --git a/netwerk/protocol/http/nsHttpChannel.cpp b/netwerk/protocol/http/nsHttpChannel.cpp
index 9caf71adc11d..7b935b2cc794 100644
--- a/netwerk/protocol/http/nsHttpChannel.cpp
+++ b/netwerk/protocol/http/nsHttpChannel.cpp
@@ -3149,18 +3149,15 @@ void nsHttpChannel::UpdateCacheDisposition(bool aSuccessfulReval,
 nsresult nsHttpChannel::ContinueProcessResponse4(nsresult rv) {
   bool doNotRender = DoNotRender3xxBody(rv);
 
-  if (rv == NS_ERROR_DOM_BAD_URI && mRedirectURI) {
-    bool isHTTP =
-        mRedirectURI->SchemeIs("http") || mRedirectURI->SchemeIs("https");
-    if (!isHTTP) {
-      // This was a blocked attempt to redirect and subvert the system by
-      // redirecting to another protocol (perhaps javascript:)
-      // In that case we want to throw an error instead of displaying the
-      // non-redirected response body.
-      LOG(("ContinueProcessResponse4 detected rejected Non-HTTP Redirection"));
-      doNotRender = true;
-      rv = NS_ERROR_CORRUPTED_CONTENT;
-    }
+  if (rv == NS_ERROR_DOM_BAD_URI && mRedirectURI &&
+      !net::SchemeIsHttpOrHttps(mRedirectURI)) {
+    // This was a blocked attempt to redirect and subvert the system by
+    // redirecting to another protocol (perhaps javascript:)
+    // In that case we want to throw an error instead of displaying the
+    // non-redirected response body.
+    LOG(("ContinueProcessResponse4 detected rejected Non-HTTP Redirection"));
+    doNotRender = true;
+    rv = NS_ERROR_CORRUPTED_CONTENT;
   }
 
   if (doNotRender) {
diff --git a/netwerk/protocol/http/nsHttpHandler.cpp b/netwerk/protocol/http/nsHttpHandler.cpp
index 043496f7b415..ac6446efeb6c 100644
--- a/netwerk/protocol/http/nsHttpHandler.cpp
+++ b/netwerk/protocol/http/nsHttpHandler.cpp
@@ -2042,7 +2042,7 @@ nsHttpHandler::NewChannel(nsIURI* uri, nsILoadInfo* aLoadInfo,
   NS_ENSURE_ARG_POINTER(result);
 
   // Verify that we have been given a valid scheme
-  if (!uri->SchemeIs("http") && !uri->SchemeIs("https")) {
+  if (!net::SchemeIsHttpOrHttps(uri)) {
     NS_WARNING("Invalid URI scheme");
     return NS_ERROR_UNEXPECTED;
   }
@@ -2866,8 +2866,7 @@ void nsHttpHandler::MaybeAddAltSvcForTesting(
     return;
   }
 
-  bool isHttps = false;
-  if (NS_FAILED(aUri->SchemeIs("https", &isHttps)) || !isHttps) {
+  if (!aUri->SchemeIs("https")) {
     // Only set for HTTPS.
     return;
   }
diff --git a/netwerk/protocol/viewsource/nsViewSourceChannel.cpp b/netwerk/protocol/viewsource/nsViewSourceChannel.cpp
index d38cc4358636..4a825ead1943 100644
--- a/netwerk/protocol/viewsource/nsViewSourceChannel.cpp
+++ b/netwerk/protocol/viewsource/nsViewSourceChannel.cpp
@@ -175,10 +175,8 @@ nsresult nsViewSourceChannel::UpdateLoadInfoResultPrincipalURI() {
     return NS_ERROR_UNEXPECTED;
   }
 
-  bool alreadyViewSource;
-  if (NS_SUCCEEDED(channelResultPrincipalURI->SchemeIs("view-source",
-                                                       &alreadyViewSource)) &&
-      alreadyViewSource) {
+  if (channelResultPrincipalURI->SchemeIs("view-source")) {
+    // already view-source
     return NS_OK;
   }
 
diff --git a/parser/html/nsHtml5DocumentBuilder.cpp b/parser/html/nsHtml5DocumentBuilder.cpp
index b2220253dc41..c6a83d302af5 100644
--- a/parser/html/nsHtml5DocumentBuilder.cpp
+++ b/parser/html/nsHtml5DocumentBuilder.cpp
@@ -78,15 +78,9 @@ void nsHtml5DocumentBuilder::SetDocumentMode(nsHtml5DocumentMode m) {
 
   if (errMsgId && !mDocument->IsLoadedAsData()) {
     nsCOMPtr<nsIURI> docURI = mDocument->GetDocumentURI();
-    bool isData = false;
-    docURI->SchemeIs("data", &isData);
-    bool isHttp = false;
-    docURI->SchemeIs("http", &isHttp);
-    bool isHttps = false;
-    docURI->SchemeIs("https", &isHttps);
-
     nsCOMPtr<nsIPrincipal> principal = mDocument->GetPrincipal();
-    if (principal->GetIsNullPrincipal() && !isData && !isHttp && !isHttps) {
+    if (principal->GetIsNullPrincipal() && !docURI->SchemeIs("data") &&
+        !mozilla::net::SchemeIsHttpOrHttps(docURI)) {
       // Don't normally warn for null principals. It may well be internal
       // documents for which the warning is not applicable.
       return;
diff --git a/parser/prototype/PrototypeDocumentParser.cpp b/parser/prototype/PrototypeDocumentParser.cpp
index c07a35b892d0..7b84d42647a6 100644
--- a/parser/prototype/PrototypeDocumentParser.cpp
+++ b/parser/prototype/PrototypeDocumentParser.cpp
@@ -13,7 +13,6 @@
 #include "nsCharsetSource.h"
 #include "nsParser.h"
 #include "mozilla/dom/Document.h"
-#include "mozilla/dom/URL.h"
 #include "mozilla/dom/PrototypeDocumentContentSink.h"
 
 using namespace mozilla::dom;
@@ -64,7 +63,7 @@ PrototypeDocumentParser::Parse(nsIURI* aURL) {
   // Look in the chrome cache: we've got this puppy loaded
   // already.
   nsXULPrototypeDocument* proto =
-      IsChromeURI(mDocumentURI)
+      mDocumentURI->SchemeIs("chrome")
           ? nsXULPrototypeCache::GetInstance()->GetPrototype(mDocumentURI)
           : nullptr;
 
@@ -183,7 +182,7 @@ nsresult PrototypeDocumentParser::PrepareToLoadPrototype(
 
   // Store the new prototype right away so if there are multiple requests
   // for the same document they all get the same prototype.
-  if (IsChromeURI(mDocumentURI) &&
+  if (mDocumentURI->SchemeIs("chrome") &&
       nsXULPrototypeCache::GetInstance()->IsEnabled()) {
     nsXULPrototypeCache::GetInstance()->PutPrototype(mCurrentPrototype);
   }
diff --git a/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingState.cpp b/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingState.cpp
index 58221f4c85bc..e5ccfbf56f79 100644
--- a/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingState.cpp
+++ b/toolkit/components/antitracking/bouncetrackingprotection/BounceTrackingState.cpp
@@ -452,7 +452,7 @@ nsresult BounceTrackingState::OnDocumentStartRequest(nsIChannel* aChannel) {
   rv = aChannel->GetURI(getter_AddRefs(channelURI));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (channelURI->SchemeIs("http") || channelURI->SchemeIs("https")) {
+  if (mozilla::net::SchemeIsHttpOrHttps(channelURI)) {
     nsCOMPtr<nsIEffectiveTLDService> tldService =
         do_GetService(NS_EFFECTIVETLDSERVICE_CONTRACTID, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
diff --git a/toolkit/components/sessionstore/SessionStoreUtils.cpp b/toolkit/components/sessionstore/SessionStoreUtils.cpp
index 2983be44146f..5a30292b2b02 100644
--- a/toolkit/components/sessionstore/SessionStoreUtils.cpp
+++ b/toolkit/components/sessionstore/SessionStoreUtils.cpp
@@ -1675,8 +1675,7 @@ void SessionStoreUtils::RestoreDocShellState(
   if (aDocShell) {
     nsCOMPtr<nsIURI> currentUri;
     nsDocShell::Cast(aDocShell)->GetCurrentURI(getter_AddRefs(currentUri));
-    if (aState.URI() &&
-        (!currentUri || mozilla::net::SchemeIsAbout(currentUri))) {
+    if (aState.URI() && (!currentUri || currentUri->SchemeIs("about"))) {
       aDocShell->SetCurrentURIForSessionStore(aState.URI());
     }
     RestoreDocShellCapabilities(aDocShell, aState.docShellCaps());
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index 35811056c34e..ead54f67d44b 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -1765,7 +1765,7 @@ nsXULAppInfo::GetServerURL(nsIURL** aServerURL) {
 NS_IMETHODIMP
 nsXULAppInfo::SetServerURL(nsIURL* aServerURL) {
   // Only allow https or http URLs
-  if (!aServerURL->SchemeIs("http") && !aServerURL->SchemeIs("https")) {
+  if (!net::SchemeIsHttpOrHttps(aServerURL)) {
     return NS_ERROR_INVALID_ARG;
   }
 
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index e23df8e6f982..c0953c6e8c91 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -3277,7 +3277,7 @@ bool nsExternalHelperAppService::GetFileNameFromChannel(nsIChannel* aChannel,
     nsAutoCString query;
 
     // We only care about the query for HTTP and HTTPS URLs
-    if (url->SchemeIs("http") || url->SchemeIs("https")) {
+    if (net::SchemeIsHttpOrHttps(url)) {
       url->GetQuery(query);
     }
 
diff --git a/uriloader/prefetch/nsPrefetchService.cpp b/uriloader/prefetch/nsPrefetchService.cpp
index 635e4e34a948..0ebe6c7738e8 100644
--- a/uriloader/prefetch/nsPrefetchService.cpp
+++ b/uriloader/prefetch/nsPrefetchService.cpp
@@ -284,7 +284,7 @@ nsPrefetchNode::AsyncOnChannelRedirect(
   nsresult rv = aNewChannel->GetURI(getter_AddRefs(newURI));
   if (NS_FAILED(rv)) return rv;
 
-  if (!newURI->SchemeIs("http") && !newURI->SchemeIs("https")) {
+  if (!net::SchemeIsHttpOrHttps(newURI)) {
     LOG(("rejected: URL is not of type http/https\n"));
     return NS_ERROR_ABORT;
   }
@@ -550,7 +550,7 @@ nsresult nsPrefetchService::CheckURIScheme(nsIURI* aURI,
   // for now, we'll only prefetch http and https links since we know that's
   // the most common case.
   //
-  if (!aURI->SchemeIs("http") && !aURI->SchemeIs("https")) {
+  if (!net::SchemeIsHttpOrHttps(aURI)) {
     LOG(("rejected: URL is not of type http/https\n"));
     return NS_ERROR_ABORT;
   }
@@ -563,7 +563,7 @@ nsresult nsPrefetchService::CheckURIScheme(nsIURI* aURI,
     return NS_ERROR_ABORT;
   }
 
-  if (!referrer->SchemeIs("http") && !referrer->SchemeIs("https")) {
+  if (!net::SchemeIsHttpOrHttps(referrer)) {
     LOG(("rejected: referrer URL is neither http nor https\n"));
     return NS_ERROR_ABORT;
   }
diff --git a/widget/android/nsWindow.cpp b/widget/android/nsWindow.cpp
index 887fc34b8b24..00f8471b4594 100644
--- a/widget/android/nsWindow.cpp
+++ b/widget/android/nsWindow.cpp
@@ -2346,7 +2346,7 @@ RefPtr<MozPromise<bool, bool, false>> nsWindow::OnLoadRequest(
   nsAutoCString spec, triggeringSpec;
   if (aUri) {
     aUri->GetDisplaySpec(spec);
-    if (aIsTopLevel && mozilla::net::SchemeIsData(aUri) &&
+    if (aIsTopLevel && aUri->SchemeIs("data") &&
         spec.Length() > MAX_TOPLEVEL_DATA_URI_LEN) {
       return MozPromise<bool, bool, false>::CreateAndResolve(false, __func__);
     }