Use IDCompositionSurface to implement DirectCompositionSurfaceWin.

content/browser/compositor/gpu_browser_compositor_output_surface.cc

Index: content/browser/compositor/gpu_browser_compositor_output_surface.cc
diff --git a/content/browser/compositor/gpu_browser_compositor_output_surface.cc b/content/browser/compositor/gpu_browser_compositor_output_surface.cc
index 1d65415c2f4de51dc5aaa7dc9afce98a507f7568..5472ad29d74e5eba1817893aaae745e83676b79b 100644
--- a/content/browser/compositor/gpu_browser_compositor_output_surface.cc
+++ b/content/browser/compositor/gpu_browser_compositor_output_surface.cc
@@ -105,6 +105,8 @@ void GpuBrowserCompositorOutputSurface::SwapBuffers(
     }
   }
 
+  set_draw_rectangle_for_frame_ = false;
+
   if (swap_rect == gfx::Rect(frame.size))
     context_provider_->ContextSupport()->Swap();
   else
@@ -133,6 +135,15 @@ void GpuBrowserCompositorOutputSurface::SetSurfaceSuspendedForRecycle(
     bool suspended) {}
 #endif
 
+void GpuBrowserCompositorOutputSurface::SetDrawRectangle(
+    const gfx::Rect& rect) {
+  if (set_draw_rectangle_for_frame_)

[sunnyps, 2017/01/28 01:33:58]

should we dcheck/check(!set_draw_rectangle_for_frame)?

[sunnyps, 2017/01/28 01:33:58]

can we dcheck/check that rect is a subrect of surface size?

+    return;
+  set_draw_rectangle_for_frame_ = true;
+  context_provider()->ContextGL()->SetDrawRectangleCHROMIUM(
+      rect.x(), rect.y(), rect.width(), rect.height());
+}
+
 gpu::CommandBufferProxyImpl*
 GpuBrowserCompositorOutputSurface::GetCommandBufferProxy() {
   ui::ContextProviderCommandBuffer* provider_command_buffer =