Offset scissor and viewport when using SetDrawRectangle on surface.

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 32 matching lines @@
   bool ScheduleOverlayPlane(int z_order,
                             gfx::OverlayTransform transform,
                             gl::GLImage* image,
                             const gfx::Rect& bounds_rect,
                             const gfx::RectF& crop_rect) override;
   bool FlipsVertically() const override;
   bool SupportsPostSubBuffer() override;
   bool OnMakeCurrent(gl::GLContext* context) override;
   bool SupportsSetDrawRectangle() 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();
 
  protected:
   ~DirectCompositionSurfaceWin() override;
 
  private:
   struct Overlay {
@@ skipping 25 matching lines @@
   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;
   std::unique_ptr<gfx::VSyncProvider> vsync_provider_;
   std::vector<Overlay> pending_overlays_;
 
+  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<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_