Set device scale factor in CompositorFrame and scale frame size in WS.

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 <unordered_map>
 
@@ skipping 31 matching lines @@
 }
 
 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 ServerWindowTracker,
                        public cc::mojom::MojoCompositorFrameSinkClient {
  public:
-  FrameGenerator(FrameGeneratorDelegate* delegate, ServerWindow* root_window);
+  FrameGenerator(FrameGeneratorDelegate* delegate,
+                 ServerWindow* root_window,
+                 float device_scale_factor);

[kylechar, 2016/12/05 14:46:11]

Instead of adding another parameter to the constructor, you could just call
frame_generator_.set_device_scale_factor(...) after the constructor?

[riajiang, 2016/12/09 19:31:44]

Done.

   ~FrameGenerator() override;
 
   // Schedules a redraw for the provided region.
   void OnAcceleratedWidgetAvailable(gfx::AcceleratedWidget widget);
 
   // Adds a reference to new surface with |surface_id| for |window|. This
   // reference is to ensure the surface is not deleted while it's still being
   // displayed. The display root surface has a reference from the top level
   // root. All child surfaces are embedded by the display root and receive a
   // reference from it.
   //
   // If a new display root Surface is created, then all child surfaces will
   // receive a reference from the new display root so they are not deleted with
   // the old display root.
   //
   // If there is an existing reference to an old surface with the same
   // FrameSinkId then that reference will be removed after the next
   // CompositorFrame is submitted.
   void OnSurfaceCreated(const cc::SurfaceId& surface_id, ServerWindow* window);
 
+  void UpdateDeviceScaleFactor(float device_scale_factor);
+
  private:
   friend class ui::ws::test::FrameGeneratorTest;
 
   // cc::mojom::MojoCompositorFrameSinkClient implementation:
   void DidReceiveCompositorFrameAck() override;
   void OnBeginFrame(const cc::BeginFrameArgs& begin_frame_arags) override;
   void ReclaimResources(const cc::ReturnedResourceArray& resources) override;
 
   // Generates the CompositorFrame.
   cc::CompositorFrame GenerateCompositorFrame(const gfx::Rect& output_rect);
@@ skipping 30 matching lines @@
   // Removes all retained references to surfaces.
   void RemoveAllSurfaceReferences();
 
   cc::mojom::DisplayCompositor* GetDisplayCompositor();
 
   // ServerWindowObserver implementation.
   void OnWindowDestroying(ServerWindow* window) override;
 
   FrameGeneratorDelegate* delegate_;
   ServerWindow* const root_window_;
+  float device_scale_factor_;
 
   gfx::Size last_submitted_frame_size_;
   cc::LocalFrameId local_frame_id_;
   cc::SurfaceIdAllocator id_allocator_;
   cc::mojom::MojoCompositorFrameSinkPtr compositor_frame_sink_;
 
   // Represents the top level root surface id that should reference the display
   // root surface. We don't know the actual value, because it's generated in
   // another process, this is used internally as a placeholder.
   const cc::SurfaceId top_level_root_surface_id_;
@@ skipping 23 matching lines @@
   base::WeakPtrFactory<FrameGenerator> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameGenerator);
 };
 
 }  // namespace ws
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_FRAME_GENERATOR_H_