Bug 1540170 - don't use history for windowless browsers, r=farre

Differential Revision: https://phabricator.services.mozilla.com/D25587

toolkit/components/browser/nsWebBrowser.cpp

@@ -102,7 +102,8 @@ nsIWidget* nsWebBrowser::EnsureWidget() {
 already_AddRefed<nsWebBrowser> nsWebBrowser::Create(
     nsIWebBrowserChrome* aContainerWindow, nsIWidget* aParentWidget,
     const OriginAttributes& aOriginAttributes,
-    dom::BrowsingContext* aBrowsingContext) {
+    dom::BrowsingContext* aBrowsingContext,
+    bool aDisableHistory /* = false */) {
   RefPtr<nsWebBrowser> browser = new nsWebBrowser(
       aBrowsingContext->IsContent() ? typeContentWrapper : typeChromeWrapper);
 
@@ -152,7 +153,7 @@ already_AddRefed<nsWebBrowser> nsWebBrowser::Create(
 
   docShell->InitSessionHistory();
 
-  if (XRE_IsParentProcess()) {
+  if (XRE_IsParentProcess() && !aDisableHistory) {
     // Hook up global history. Do not fail if we can't - just warn.
     DebugOnly<nsresult> rv =
         browser->EnableGlobalHistory(browser->mShouldEnableHistory);

toolkit/components/browser/nsWebBrowser.h

@@ -108,7 +108,8 @@ class nsWebBrowser final : public nsIWebBrowser,
   static already_AddRefed<nsWebBrowser> Create(
       nsIWebBrowserChrome* aContainerWindow, nsIWidget* aParentWidget,
       const mozilla::OriginAttributes& aOriginAttributes,
-      mozilla::dom::BrowsingContext* aBrowsingContext);
+      mozilla::dom::BrowsingContext* aBrowsingContext,
+      bool aDisableHistory = false);
 
  protected:
   virtual ~nsWebBrowser();

xpfe/appshell/nsAppShellService.cpp

@@ -495,7 +495,8 @@ nsAppShellService::CreateWindowlessBrowser(bool aIsChrome,
    * an associated doc shell, which is what we're interested in.
    */
   nsCOMPtr<nsIWebBrowser> browser =
-      nsWebBrowser::Create(stub, widget, OriginAttributes(), browsingContext);
+      nsWebBrowser::Create(stub, widget, OriginAttributes(), browsingContext,
+                           true /* disable history */);
 
   if (NS_WARN_IF(!browser)) {
     NS_ERROR("Couldn't create instance of nsWebBrowser!");