[cc]: Add a BeginMainFrameNotExpectedSoon signal and route it to the RendererScheduler.

mojo/services/html_viewer/weblayertreeview_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SERVICES_HTML_VIEWER_WEBLAYERTREEVIEW_IMPL_H_
 #define MOJO_SERVICES_HTML_VIEWER_WEBLAYERTREEVIEW_IMPL_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 33 matching lines @@
       mojo::GpuPtr gpu_service);
   virtual ~WebLayerTreeViewImpl();
 
   void set_widget(blink::WebWidget* widget) { widget_ = widget; }
   void set_view(mojo::View* view) { view_ = view; }
 
   // cc::LayerTreeHostClient implementation.
   void WillBeginMainFrame() override;
   void DidBeginMainFrame() override;
   void BeginMainFrame(const cc::BeginFrameArgs& args) override;
+  void BeginMainFrameNotExpectedSoon() override;
   void Layout() override;
   void ApplyViewportDeltas(const gfx::Vector2dF& inner_delta,
                            const gfx::Vector2dF& outer_delta,
                            const gfx::Vector2dF& elastic_overscroll_delta,
                            float page_scale,
                            float top_controls_delta) override;
   void ApplyViewportDeltas(const gfx::Vector2d& scroll_delta,
                            float page_scale,
                            float top_controls_delta) override;
   void RequestNewOutputSurface() override;
@@ skipping 63 matching lines @@
       main_thread_compositor_task_runner_;
   base::WeakPtr<WebLayerTreeViewImpl> main_thread_bound_weak_ptr_;
 
   base::WeakPtrFactory<WebLayerTreeViewImpl> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(WebLayerTreeViewImpl);
 };
 
 }  // namespace html_viewer
 
 #endif  // MOJO_SERVICES_HTML_VIEWER_WEBLAYERTREEVIEW_IMPL_H_