Bug 1781936 - Propagate GeckoView settings on BrowsingContext replace…

…ment. r=nika

This should be a better fix. GeckoView assumes these don't change on .top
unless they are explicitly set.

I don't have an Android build environment handy, but I'll try to confirm.

Also, remove an unused flag while at it.

Differential Revision: https://phabricator.services.mozilla.com/D153107

docshell/base/CanonicalBrowsingContext.cpp

@@ -314,6 +314,16 @@ void CanonicalBrowsingContext::ReplacedBy(
   txn.SetEmbedderColorScheme(GetEmbedderColorScheme());
   txn.SetHasRestoreData(GetHasRestoreData());
   txn.SetShouldDelayMediaFromStart(GetShouldDelayMediaFromStart());
+
+  // Propagate some settings on BrowsingContext replacement so they're not lost
+  // on bfcached navigations. These are important for GeckoView (see bug
+  // 1781936).
+  txn.SetAllowJavascript(GetAllowJavascript());
+  txn.SetForceEnableTrackingProtection(GetForceEnableTrackingProtection());
+  txn.SetUserAgentOverride(GetUserAgentOverride());
+  txn.SetSuspendMediaWhenInactive(GetSuspendMediaWhenInactive());
+  txn.SetDisplayMode(GetDisplayMode());
+
   // As this is a different BrowsingContext, set InitialSandboxFlags to the
   // current flags in the new context so that they also apply to any initial
   // about:blank documents created in it.

docshell/base/nsDocShell.cpp

@@ -390,7 +390,6 @@ nsDocShell::nsDocShell(BrowsingContext* aBrowsingContext,
       mTitleValidForCurrentURI(false),
       mWillChangeProcess(false),
       mIsNavigating(false),
-      mSuspendMediaWhenInactive(false),
       mForcedAutodetection(false),
       mCheckingSessionHistory(false),
       mNeedToReportActiveAfterLoadingBecomesActive(false) {

docshell/base/nsDocShell.h

@@ -1362,10 +1362,6 @@ class nsDocShell final : public nsDocLoader,
   // nsIWebNavigation navigation method.
   bool mIsNavigating : 1;
 
-  // This flag indicates whether the media in this docshell should be suspended
-  // when the docshell is inactive.
-  bool mSuspendMediaWhenInactive : 1;
-
   // Whether we have a pending encoding autodetection request from the
   // menu for all encodings.
   bool mForcedAutodetection : 1;