Allow switching DirectCompositionSurfaceWin between drawing modes.

gpu/ipc/service/direct_composition_surface_win.h

 // Copyright 2017 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 GPU_IPC_SERVICE_DIRECT_COMPOSITION_SURFACE_WIN_H_
 #define GPU_IPC_SERVICE_DIRECT_COMPOSITION_SURFACE_WIN_H_
 
 #include <d3d11.h>
 #include <dcomp.h>
 #include <windows.h>
@@ skipping 27 matching lines @@
               float scale_factor,
               bool has_alpha) override;
   gfx::SwapResult SwapBuffers() override;
   gfx::SwapResult PostSubBuffer(int x, int y, int width, int height) override;
   gfx::VSyncProvider* GetVSyncProvider() override;
   bool ScheduleOverlayPlane(int z_order,
                             gfx::OverlayTransform transform,
                             gl::GLImage* image,
                             const gfx::Rect& bounds_rect,
                             const gfx::RectF& crop_rect) override;
+  bool SetEnableDCLayers(bool enable) override;
   bool FlipsVertically() const override;
   bool SupportsPostSubBuffer() override;
   bool OnMakeCurrent(gl::GLContext* context) override;
-  bool SupportsSetDrawRectangle() const override;
+  bool SupportsDCLayers() const override;
   bool SetDrawRectangle(const gfx::Rect& rect) override;
   gfx::Vector2d GetDrawOffset() const override;
 
   bool Initialize(std::unique_ptr<gfx::VSyncProvider> vsync_provider);
 
   scoped_refptr<base::TaskRunner> GetWindowTaskRunnerForTesting();
+  const base::win::ScopedComPtr<IDXGISwapChain1> swap_chain() const {

[sunnyps, 2017/03/21 00:19:00]

nit: operator-> on ScopedComPtr is const so the first const declaration here
doesn't do anything.

nit: can you rename this to swap_chain_for_testing?

+    return swap_chain_;
+  }
 
  protected:
   ~DirectCompositionSurfaceWin() override;
 
  private:
   struct Overlay {
     Overlay(int z_order,
             gfx::OverlayTransform transform,
             scoped_refptr<gl::GLImage> image,
             gfx::Rect bounds_rect,
             gfx::RectF crop_rect);
     Overlay(const Overlay& overlay);
 
     ~Overlay();
 
     int z_order;
     gfx::OverlayTransform transform;
     scoped_refptr<gl::GLImage> image;
     gfx::Rect bounds_rect;
     gfx::RectF crop_rect;
   };
 
   bool CommitAndClearPendingOverlays();
+  void ReleaseCurrentSurface();
   void InitializeSurface();
-  void ReleaseDrawTexture();
+  // Release the texture that's currently being drawn to. If will_discard is
+  // true then the surface should be discarded without swapping any contents
+  // to it.
+  void ReleaseDrawTexture(bool will_discard);
 
   ChildWindowWin child_window_;
 
   HWND window_ = nullptr;
   // This is a placeholder surface used when not rendering to the
   // DirectComposition surface.
   EGLSurface default_surface_ = 0;
 
   // This is the real surface representing the backbuffer. It may be null
   // outside of a BeginDraw/EndDraw pair.
   EGLSurface real_surface_ = 0;
   gfx::Size size_ = gfx::Size(1, 1);
   bool first_swap_ = true;
+  bool enable_dc_layers_ = false;
   std::unique_ptr<gfx::VSyncProvider> vsync_provider_;
   std::vector<Overlay> pending_overlays_;
+  gfx::Rect swap_rect_;
 
   gfx::Vector2d draw_offset_;
 
   base::win::ScopedComPtr<ID3D11Device> d3d11_device_;
   base::win::ScopedComPtr<IDCompositionDevice2> dcomp_device_;
   base::win::ScopedComPtr<IDCompositionTarget> dcomp_target_;
   base::win::ScopedComPtr<IDCompositionVisual2> visual_;
   base::win::ScopedComPtr<IDCompositionSurface> dcomp_surface_;
+  base::win::ScopedComPtr<IDXGISwapChain1> swap_chain_;
   base::win::ScopedComPtr<ID3D11Texture2D> draw_texture_;
 
   // Keep track of whether the texture has been rendered to, as the first draw
   // to it must overwrite the entire thing.
   bool has_been_rendered_to_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(DirectCompositionSurfaceWin);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_IPC_SERVICE_DIRECT_COMPOSITION_SURFACE_WIN_H_