cc: Don't do CompositeAndReadback when using DelegatingRenderer.

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 <utility>
 #include <vector>
 
 #include "base/debug/trace_event.h"
@@ skipping 108 matching lines @@
   return scissor_rect_in_canvas_space;
 }
 
 DirectRenderer::DirectRenderer(RendererClient* client,
                                ResourceProvider* resource_provider)
     : Renderer(client),
       resource_provider_(resource_provider) {}
 
 DirectRenderer::~DirectRenderer() {}
 
+bool DirectRenderer::CanReadPixels() const { return true; }
+
 void DirectRenderer::SetEnlargePassTextureAmountForTesting(
     gfx::Vector2d amount) {
   enlarge_pass_texture_amount_ = amount;
 }
 
 void DirectRenderer::DecideRenderPassAllocationsForFrame(
     const RenderPassList& render_passes_in_draw_order) {
   base::hash_map<RenderPass::Id, const RenderPass*> render_passes_in_frame;
   for (size_t i = 0; i < render_passes_in_draw_order.size(); ++i)
     render_passes_in_frame.insert(std::pair<RenderPass::Id, const RenderPass*>(
@@ skipping 212 matching lines @@
 gfx::Size DirectRenderer::RenderPassTextureSize(const RenderPass* render_pass) {
   return render_pass->output_rect.size();
 }
 
 // static
 GLenum DirectRenderer::RenderPassTextureFormat(const RenderPass* render_pass) {
   return GL_RGBA;
 }
 
 }  // namespace cc