Bug 1576298 - Remove DeviceSizeIsPageSize from nsDocShell and nsPresContext. r=emilio

This comes from bug 890195, and it was superseded by bug 1575097.

This isn't used for anything anymore, and we can remove the otherwise unused
MediaFeatureChangeReason flag as well.

Differential Revision: https://phabricator.services.mozilla.com/D174492

docshell/base/nsDocShell.cpp

@@ -352,7 +352,6 @@ nsDocShell::nsDocShell(BrowsingContext* aBrowsingContext,
       mAllowAuth(mItemType == typeContent),
       mAllowKeywordFixup(false),
       mDisableMetaRefreshWhenInactive(false),
-      mDeviceSizeIsPageSize(false),
       mWindowDraggingAllowed(false),
       mInFrameSwap(false),
       mFiredUnloadEvent(false),
@@ -442,9 +441,6 @@ bool nsDocShell::Initialize() {
       Preferences::GetBool("browser.meta_refresh_when_inactive.disabled",
                            mDisableMetaRefreshWhenInactive);
 
-  mDeviceSizeIsPageSize = Preferences::GetBool(
-      "docshell.device_size_is_page_size", mDeviceSizeIsPageSize);
-
   if (nsCOMPtr<nsIObserverService> serv = services::GetObserverService()) {
     const char* msg = mItemType == typeContent ? NS_WEBNAVIGATION_CREATE
                                                : NS_CHROME_WEBNAVIGATION_CREATE;
@@ -3196,26 +3192,6 @@ nsDocShell::GetIsNavigating(bool* aOut) {
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsDocShell::SetDeviceSizeIsPageSize(bool aValue) {
-  if (mDeviceSizeIsPageSize != aValue) {
-    mDeviceSizeIsPageSize = aValue;
-    RefPtr<nsPresContext> presContext = GetPresContext();
-    if (presContext) {
-      presContext->MediaFeatureValuesChanged(
-          {MediaFeatureChangeReason::DeviceSizeIsPageSizeChange},
-          MediaFeatureChangePropagation::JustThisDocument);
-    }
-  }
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsDocShell::GetDeviceSizeIsPageSize(bool* aValue) {
-  *aValue = mDeviceSizeIsPageSize;
-  return NS_OK;
-}
-
 void nsDocShell::ClearFrameHistory(nsISHEntry* aEntry) {
   MOZ_ASSERT(!mozilla::SessionHistoryInParent());
   RefPtr<ChildSHistory> rootSH = GetRootSessionHistory();