Revert of FrameGenerator should not be created until an AcceleratedWidget is available

services/ui/ws/frame_generator.h

 // Copyright 2016 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 SERVICES_UI_WS_FRAME_GENERATOR_H_
 #define SERVICES_UI_WS_FRAME_GENERATOR_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 21 matching lines @@
 class FrameGeneratorTest;
 }
 
 class FrameGeneratorDelegate;
 class ServerWindow;
 
 // Responsible for redrawing the display in response to the redraw requests by
 // submitting CompositorFrames to the owned CompositorFrameSink.
 class FrameGenerator : public cc::mojom::MojoCompositorFrameSinkClient {
  public:
-  FrameGenerator(FrameGeneratorDelegate* delegate,
-                 ServerWindow* root_window,
-                 gfx::AcceleratedWidget widget);
+  FrameGenerator(FrameGeneratorDelegate* delegate, ServerWindow* root_window);
   ~FrameGenerator() override;
 
   void SetDeviceScaleFactor(float device_scale_factor);
 
+  // Schedules a redraw for the provided region.
+  void OnAcceleratedWidgetAvailable(gfx::AcceleratedWidget widget);
+
   // Updates the WindowManager's SurfaceInfo.
   void OnSurfaceCreated(const cc::SurfaceInfo& surface_info);
 
   void OnWindowDamaged();
 
  private:
   friend class ui::ws::test::FrameGeneratorTest;
 
   // cc::mojom::MojoCompositorFrameSinkClient implementation:
   void DidReceiveCompositorFrameAck() override;
@@ skipping 24 matching lines @@
   mojo::Binding<cc::mojom::MojoCompositorFrameSinkClient> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameGenerator);
 };
 
 }  // namespace ws
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_FRAME_GENERATOR_H_