mus: Embedder can request and observe BeginFrame for embedded client.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index b92c30d53797f4b7c2c0fb7b283a98f1b774af6e..37e28baca6eb7e0ea61ad842c05ee099132867b7 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -655,12 +655,12 @@ void RenderWidgetHostViewAura::OnSetNeedsFlushInput() {
   UpdateNeedsBeginFramesInternal();
 }
 
-void RenderWidgetHostViewAura::OnBeginFrame(
-    const cc::BeginFrameArgs& args) {
+void RenderWidgetHostViewAura::OnBeginFrame(const cc::BeginFrameArgs& args) {
   needs_flush_input_ = false;
   host_->FlushInput();
   UpdateNeedsBeginFramesInternal();
-  host_->Send(new ViewMsg_BeginFrame(host_->GetRoutingID(), args));
+  if (!IsMus())
+    host_->Send(new ViewMsg_BeginFrame(host_->GetRoutingID(), args));
 }
 
 RenderFrameHostImpl* RenderWidgetHostViewAura::GetFocusedFrame() {
@@ -2387,10 +2387,17 @@ void RenderWidgetHostViewAura::SetPopupChild(
 }
 
 void RenderWidgetHostViewAura::UpdateNeedsBeginFramesInternal() {
-  if (!delegated_frame_host_)
+  bool needs_begin_frames = needs_begin_frames_ || needs_flush_input_;
+  if (delegated_frame_host_) {
+    delegated_frame_host_->SetNeedsBeginFrames(needs_begin_frames);
+    return;
+  }
+  if (!IsMus())
     return;
-  delegated_frame_host_->SetNeedsBeginFrames(needs_begin_frames_ ||
-                                             needs_flush_input_);
+  window()->SetNeedsBeginFrames(
+      needs_begin_frames_ || needs_flush_input_,
+      base::Bind(&RenderWidgetHostViewAura::OnBeginFrame,
+                 weak_ptr_factory_.GetWeakPtr(), cc::BeginFrameArgs()));
 }
 
 }  // namespace content