Don't use fallback frame sinks on Android

content/renderer/gpu/render_widget_compositor.h

Index: content/renderer/gpu/render_widget_compositor.h
diff --git a/content/renderer/gpu/render_widget_compositor.h b/content/renderer/gpu/render_widget_compositor.h
index 1da6b8b6b82ca5ef80d46a593364495e83ad593e..975b0da23a689119ab349e98d8f6a7dccb303f79 100644
--- a/content/renderer/gpu/render_widget_compositor.h
+++ b/content/renderer/gpu/render_widget_compositor.h
@@ -211,7 +211,12 @@ class CONTENT_EXPORT RenderWidgetCompositor
 
   enum {
     COMPOSITOR_FRAME_SINK_RETRIES_BEFORE_FALLBACK = 4,
+#ifdef OS_ANDROID
+    // On Android, we don't use fallback frame sinks. (crbug.com/721102)

[enne (OOO), 2017/05/12 16:46:59]

This is a little subtle, and I think folks looking at rwc.cc won't realize that
Android never has a fallback. Could you add a #ifdef OS_ANDROID and
LOG_IF(FATAL, ...) in RWC::RequestNewCompositorFrameSink if fallback is true?

[Saman Sami, 2017/05/12 17:12:45]

Done.

+    MAX_COMPOSITOR_FRAME_SINK_RETRIES = 4,
+#else
     MAX_COMPOSITOR_FRAME_SINK_RETRIES = 5,
+#endif
   };
 
  protected: