Use IDCompositionSurface to implement DirectCompositionSurfaceWin.

content/browser/compositor/gpu_browser_compositor_output_surface.cc

 // Copyright 2014 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.
 
 #include "content/browser/compositor/gpu_browser_compositor_output_surface.h"
 
 #include <utility>
 
 #include "build/build_config.h"
 #include "cc/output/output_surface_client.h"
@@ skipping 66 matching lines @@
 }
 
 void GpuBrowserCompositorOutputSurface::BindFramebuffer() {
   context_provider()->ContextGL()->BindFramebuffer(GL_FRAMEBUFFER, 0);
 }
 
 void GpuBrowserCompositorOutputSurface::Reshape(
     const gfx::Size& size,
     float device_scale_factor,
     const gfx::ColorSpace& color_space,
     bool has_alpha) {

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

can we add a flag to check if set draw rect after reshape is for the full
surface size?

   context_provider()->ContextGL()->ResizeCHROMIUM(
       size.width(), size.height(), device_scale_factor, has_alpha);
 }
 
 void GpuBrowserCompositorOutputSurface::SwapBuffers(
     cc::OutputSurfaceFrame frame) {
   GetCommandBufferProxy()->SetLatencyInfo(frame.latency_info);
 
   gfx::Rect swap_rect = frame.sub_buffer_rect;
   gfx::Size surface_size = frame.size;
   if (reflector_) {
     if (swap_rect == gfx::Rect(surface_size)) {
       reflector_texture_->CopyTextureFullImage(surface_size);
       reflector_->OnSourceSwapBuffers(surface_size);
     } else {
       reflector_texture_->CopyTextureSubImage(swap_rect);
       reflector_->OnSourcePostSubBuffer(swap_rect, surface_size);
     }
   }
 
+  set_draw_rectangle_for_frame_ = false;
+
   if (swap_rect == gfx::Rect(frame.size))
     context_provider_->ContextSupport()->Swap();
   else
     context_provider_->ContextSupport()->PartialSwapBuffers(swap_rect);
 }
 
 uint32_t GpuBrowserCompositorOutputSurface::GetFramebufferCopyTextureFormat() {
   auto* gl = static_cast<ui::ContextProviderCommandBuffer*>(context_provider());
   return gl->GetCopyTextureInternalFormat();
 }
 
 bool GpuBrowserCompositorOutputSurface::IsDisplayedAsOverlayPlane() const {
   return false;
 }
 
 unsigned GpuBrowserCompositorOutputSurface::GetOverlayTextureId() const {
   return 0;
 }
 
 bool GpuBrowserCompositorOutputSurface::SurfaceIsSuspendForRecycle() const {
   return false;
 }
 
 #if defined(OS_MACOSX)
 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 =
       static_cast<ui::ContextProviderCommandBuffer*>(context_provider_.get());
   gpu::CommandBufferProxyImpl* command_buffer_proxy =
       provider_command_buffer->GetCommandBufferProxy();
   DCHECK(command_buffer_proxy);
   return command_buffer_proxy;
 }
 
 }  // namespace content