Dispatch fullscreen change notification on recreated sessions (#3196)

* Dispatch fullscreen change notification on recreated sessions

* Do not restore composited when exiting fullscreen

Author: MortimerGoro

app/src/common/shared/org/mozilla/vrbrowser/browser/engine/Session.java

@@ -512,6 +512,8 @@ private GeckoSession createGeckoSession(@NonNull SessionSettings aSettings) {
     }
 
     public void recreateSession() {
+        boolean wasFullScreen = mState.mFullScreen;
+
         SessionState previous = mState;
         mState = mState.recreate();
 
@@ -529,6 +531,12 @@ public void recreateSession() {
         for (SessionChangeListener listener : mSessionChangeListeners) {
             listener.onCurrentSessionChange(previousGeckoSession, mState.mSession);
         }
+
+        if (wasFullScreen != mState.mFullScreen) {
+            for (GeckoSession.ContentDelegate listener : mContentListeners) {
+                listener.onFullScreen(mState.mSession, mState.mFullScreen);
+            }
+        }
     }
 
     private void closeSession(@NonNull SessionState aState) {

app/src/common/shared/org/mozilla/vrbrowser/ui/widgets/NavigationBarWidget.java

@@ -557,6 +557,7 @@ private void cleanSession(@NonNull Session aSession) {
     public void onSessionChanged(@NonNull Session aOldSession, @NonNull Session aSession) {
         cleanSession(aOldSession);
         setUpSession(aSession);
+        exitFullScreenMode();
     }
 
     @Override

app/src/common/shared/org/mozilla/vrbrowser/ui/widgets/WindowWidget.java

@@ -917,8 +917,12 @@ public void saveBeforeFullscreenPlacement() {
     }
 
     public void restoreBeforeFullscreenPlacement() {
+        // We need to process `composited` separately to handle GV content process onCrash/onKill.
+        // Composited is false after a content crash but it was true when the placement was saved.
+        boolean composited = mWidgetPlacement.composited;
         mWindowPlacement = mWindowPlacementBeforeFullscreen;
         mWidgetPlacement.copyFrom(mPlacementBeforeFullscreen);
+        mWidgetPlacement.composited = composited;
     }
 
     public WidgetPlacement getBeforeFullscreenPlacement() {