Use IDCompositionSurface to implement DirectCompositionSurfaceWin.

cc/output/direct_renderer.cc

Index: cc/output/direct_renderer.cc
diff --git a/cc/output/direct_renderer.cc b/cc/output/direct_renderer.cc
index d0798231bcb21092967c4ca6161b0881e6b54360..e34a331f06f54b05bf6d095adce847d17acee0db 100644
--- a/cc/output/direct_renderer.cc
+++ b/cc/output/direct_renderer.cc
@@ -87,6 +87,11 @@ void DirectRenderer::Initialize() {
       context_provider->ContextCapabilities().commit_overlay_planes)
     allow_empty_swap_ = true;
 
+  if (context_provider &&
+      context_provider->ContextCapabilities().set_draw_rectangle) {
+    use_set_draw_rectangle_ = true;
+  }
+
   initialized_ = true;
 }
 
@@ -498,10 +503,11 @@ void DirectRenderer::DrawRenderPass(DrawingFrame* frame,
         ComputeScissorRectForRenderPass(frame));
   }
 
-  bool render_pass_is_clipped =
-      !render_pass_scissor_in_draw_space.Contains(surface_rect_in_draw_space);
   bool is_root_render_pass =
       frame->current_render_pass == frame->root_render_pass;
+  bool render_pass_is_clipped =
+      (use_set_draw_rectangle_ && is_root_render_pass) ||
+      !render_pass_scissor_in_draw_space.Contains(surface_rect_in_draw_space);
   bool has_external_stencil_test =
       is_root_render_pass && output_surface_->HasExternalStencilTest();
   bool should_clear_surface =
@@ -575,6 +581,10 @@ bool DirectRenderer::UseRenderPass(DrawingFrame* frame,
   frame->current_texture = NULL;

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

nit: nullptr

   if (render_pass == frame->root_render_pass) {
     BindFramebufferToOutputSurface(frame);
+
+    if (use_set_draw_rectangle_)
+      output_surface_->SetDrawRectangle(frame->root_damage_rect);
+
     InitializeViewport(frame, render_pass->output_rect,
                        gfx::Rect(frame->device_viewport_size),
                        frame->device_viewport_size);