Use IDCompositionSurface to implement DirectCompositionSurfaceWin.

cc/output/direct_renderer.cc

 // Copyright 2012 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 "cc/output/direct_renderer.h"
 
 #include <stddef.h>
 
 #include <unordered_map>
 #include <utility>
@@ skipping 69 matching lines @@
   overlay_processor_->Initialize();
 
   auto* context_provider = output_surface_->context_provider();
 
   use_partial_swap_ = settings_->partial_swap_enabled && CanPartialSwap();
   allow_empty_swap_ = use_partial_swap_;
   if (context_provider &&
       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;
 }
 
 // static
 gfx::RectF DirectRenderer::QuadVertexRect() {
   return gfx::RectF(-0.5f, -0.5f, 1.f, 1.f);
 }
 
 // static
 void DirectRenderer::QuadRectTransform(gfx::Transform* quad_rect_transform,
@@ skipping 391 matching lines @@
   if (frame->current_render_pass == frame->root_render_pass) {
     render_pass_scissor_in_draw_space.Intersect(
         DeviceViewportRectInDrawSpace(frame));
   }
 
   if (use_partial_swap_) {
     render_pass_scissor_in_draw_space.Intersect(
         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 =
       !has_external_stencil_test &&
       (!is_root_render_pass || settings_->should_clear_root_render_pass);
 
   // If |has_external_stencil_test| we can't discard or clear. Make sure we
   // don't need to.
   DCHECK(!has_external_stencil_test ||
          !frame->current_render_pass->has_transparent_background);
@@ skipping 50 matching lines @@
     DoDrawQuad(frame, &quad, nullptr);
   }
   FlushPolygons(&poly_list, frame, render_pass_scissor_in_draw_space,
                 render_pass_is_clipped);
   FinishDrawingQuadList();
 }
 
 bool DirectRenderer::UseRenderPass(DrawingFrame* frame,
                                    const RenderPass* render_pass) {
   frame->current_render_pass = render_pass;
   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);
     return true;
   }
 
   ScopedResource* texture = render_pass_textures_[render_pass->id].get();
   DCHECK(texture);
 
   gfx::Size size = RenderPassTextureSize(render_pass);
@@ skipping 20 matching lines @@
   auto iter = render_pass_textures_.find(render_pass_id);
   return iter != render_pass_textures_.end() && iter->second->id();
 }
 
 // static
 gfx::Size DirectRenderer::RenderPassTextureSize(const RenderPass* render_pass) {
   return render_pass->output_rect.size();
 }
 
 }  // namespace cc