Remove uses of external begin frame sources

content/renderer/render_widget.h

 // Copyright (c) 2012 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 CONTENT_RENDERER_RENDER_WIDGET_H_
 #define CONTENT_RENDERER_RENDER_WIDGET_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 193 matching lines @@
 
   // RenderWidgetCompositorDelegate
   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 BeginMainFrame(double frame_time_sec) override;
   std::unique_ptr<cc::OutputSurface> CreateOutputSurface(
       bool fallback) override;
-  std::unique_ptr<cc::BeginFrameSource> CreateExternalBeginFrameSource()
-      override;
   void DidCommitAndDrawCompositorFrame() override;
   void DidCommitCompositorFrame() override;
   void DidCompletePageScaleAnimation() override;
   void DidCompleteSwapBuffers() override;
   void ForwardCompositorProto(const std::vector<uint8_t>& proto) override;
   bool IsClosing() const override;
   void OnSwapBuffersAborted() override;
   void OnSwapBuffersComplete() override;
   void OnSwapBuffersPosted() override;
   void RequestScheduleAnimation() override;
@@ skipping 583 matching lines @@
   // This reference is set by the RenderFrame and is used to query the IME-
   // related state from the plugin to later send to the browser.
   PepperPluginInstanceImpl* focused_pepper_plugin_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_