Fix OOPIFs on Android

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 99dfbd0062dad04a101f86399cc2ce3ff30fdb94..3b0970700160eba94d1386cda44a9e9aa29f1cbe 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -1303,6 +1303,11 @@ void RenderWidgetHostViewAndroid::StartObservingRootWindow() {
   uint32_t outstanding_vsync_requests = outstanding_vsync_requests_;
   outstanding_vsync_requests_ = 0;
   RequestVSyncUpdate(outstanding_vsync_requests);
+
+  ui::WindowAndroidCompositor* compositor =
+      content_view_core_->GetWindowAndroid()->GetCompositor();

[enne (OOO), 2016/09/23 22:58:09]

Can I assume that there's always a compositor at this point? It's a little weird
to me that RenderWidgetHostViewAndroid never gets OnAttachCompositor messages,
but maybe it starts observing after the compositor is attached to the window.

[no sievers, 2016/09/23 23:16:09]

I don't trust the logic here with 'observing' but maybe you can sidestep it
since you only care about making sure that you catch all cases of attaching to a
different browser compositor.

So instead of here, I'd register the namespace in the RWHVA constructor
(null-check for compositor because of webview).

Then I'd simply unregister the namespace in OnDetachCompositor() and register it
in OnAttachCompositor().

It's possible that it will cause some redundant calls. I assume that's fine for
unregister. But not sure about registering twice. Maybe you need to track the
current compositor SurfaceClientId here?

+  delegated_frame_host_->RegisterSurfaceNamespaceHierarchy(
+      compositor->GetSurfaceClientId());
 }
 
 void RenderWidgetHostViewAndroid::StopObservingRootWindow() {
@@ -1321,6 +1326,7 @@ void RenderWidgetHostViewAndroid::StopObservingRootWindow() {
   if (host_)
     host_->Send(new ViewMsg_SetBeginFramePaused(host_->GetRoutingID(), true));
   content_view_core_->GetWindowAndroid()->RemoveObserver(this);
+  delegated_frame_host_->UnregisterSurfaceNamespaceHierarchy();
 }
 
 void RenderWidgetHostViewAndroid::SendBeginFrame(base::TimeTicks frame_time,