sync compositor: Signal async frame on IO thread

android_webview/browser/browser_view_renderer.h

Index: android_webview/browser/browser_view_renderer.h
diff --git a/android_webview/browser/browser_view_renderer.h b/android_webview/browser/browser_view_renderer.h
index cc3177b4bd43907694345bf75832001318767063..c3169cbcddb088b560f0e9d34a37c86efc86ea8a 100644
--- a/android_webview/browser/browser_view_renderer.h
+++ b/android_webview/browser/browser_view_renderer.h
@@ -130,9 +130,6 @@ class BrowserViewRenderer : public content::SynchronousCompositorClient,
                      const gfx::Vector2dF& latest_overscroll_delta,
                      const gfx::Vector2dF& current_fling_velocity) override;
   ui::TouchHandleDrawable* CreateDrawable() override;
-  void OnDrawHardwareProcessFrameFuture(
-      const scoped_refptr<content::SynchronousCompositor::FrameFuture>&
-          frame_future) override;
 
   // CompositorFrameProducer overrides
   void OnParentDrawConstraintsUpdated(
@@ -204,6 +201,9 @@ class BrowserViewRenderer : public content::SynchronousCompositorClient,
 
   bool offscreen_pre_raster_;
 
+  // TODO(boliu): Wait on render thread and remove this.
+  bool first_sync_frame_;
+
   gfx::Vector2d last_on_draw_scroll_offset_;
   gfx::Rect last_on_draw_global_visible_rect_;