Bug 1588484 - Disable Advanced Layers for now when using fission for the window. r=kmag

Differential Revision: https://phabricator.services.mozilla.com/D53759

--HG--
extra : moz-landing-system : lando

modules/libpref/init/StaticPrefList.yaml

@@ -4151,6 +4151,12 @@
   value: false
   mirror: always
 
+# Whether we allow advanced layers with fission
+- name: layers.advanced.fission.enabled
+  type: bool
+  value: false
+  mirror: always
+
 # Whether we allow AMD switchable graphics.
 - name: layers.amd-switchable-gfx.enabled
   type: bool

widget/nsBaseWidget.cpp

@@ -172,6 +172,7 @@ nsBaseWidget::nsBaseWidget()
       mPopupLevel(ePopupLevelTop),
       mPopupType(ePopupTypeAny),
       mHasRemoteContent(false),
+      mFissionWindow(false),
       mUpdateCursor(true),
       mUseAttachedEvents(false),
       mIMEHasFocus(false),
@@ -391,6 +392,7 @@ void nsBaseWidget::BaseCreate(nsIWidget* aParent, nsWidgetInitData* aInitData) {
     mPopupLevel = aInitData->mPopupLevel;
     mPopupType = aInitData->mPopupHint;
     mHasRemoteContent = aInitData->mHasRemoteContent;
+    mFissionWindow = aInitData->mFissionWindow;
   }
 
   if (aParent) {
@@ -1213,7 +1215,11 @@ already_AddRefed<LayerManager> nsBaseWidget::CreateCompositorSession(
     bool enableAPZ = UseAPZ();
     CompositorOptions options(enableAPZ, enableWR);
 
-    bool enableAL = gfx::gfxConfig::IsEnabled(gfx::Feature::ADVANCED_LAYERS);
+    // Bug 1588484 - Advanced Layers is currently disabled for fission windows,
+    // since it doesn't properly support nested RefLayers.
+    bool enableAL =
+        gfx::gfxConfig::IsEnabled(gfx::Feature::ADVANCED_LAYERS) &&
+        (!mFissionWindow || StaticPrefs::layers_advanced_fission_enabled());
     options.SetUseAdvancedLayers(enableAL);
 
 #ifdef MOZ_WIDGET_ANDROID

widget/nsBaseWidget.h

@@ -691,6 +691,7 @@ class nsBaseWidget : public nsIWidget, public nsSupportsWeakReference {
   nsPopupType mPopupType;
   SizeConstraints mSizeConstraints;
   bool mHasRemoteContent;
+  bool mFissionWindow;
 
   bool mUpdateCursor;
   bool mUseAttachedEvents;

widget/nsWidgetInitData.h

@@ -112,7 +112,8 @@ struct nsWidgetInitData {
         mMouseTransparent(false),
         mHasRemoteContent(false),
         mAlwaysOnTop(false),
-        mPIPWindow(false) {}
+        mPIPWindow(false),
+        mFissionWindow(false) {}
 
   nsWindowType mWindowType;
   nsBorderStyle mBorderStyle;
@@ -140,6 +141,8 @@ struct nsWidgetInitData {
   bool mAlwaysOnTop;
   // Is PictureInPicture window
   bool mPIPWindow;
+  // True if fission is enabled for this window
+  bool mFissionWindow;
 };
 
 #endif  // nsWidgetInitData_h__

xpfe/appshell/nsAppShellService.cpp

@@ -593,6 +593,9 @@ nsresult nsAppShellService::JustCreateTopWindow(
   if (aChromeMask & nsIWebBrowserChrome::CHROME_ALWAYS_ON_TOP)
     widgetInitData.mAlwaysOnTop = true;
 
+  if (aChromeMask & nsIWebBrowserChrome::CHROME_FISSION_WINDOW)
+    widgetInitData.mFissionWindow = true;
+
 #ifdef MOZ_WIDGET_GTK
   // Linux/Gtk PIP window support. It's Chrome Toplevel window, always on top
   // and without any bar.