cc: Make async readback path use async glRreadPixels.

cc/test/pixel_test.cc

 // Copyright 2013 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/test/pixel_test.h"
 
 #include "base/path_service.h"
+#include "base/run_loop.h"
 #include "cc/output/compositor_frame_metadata.h"
 #include "cc/output/gl_renderer.h"
 #include "cc/output/output_surface.h"
 #include "cc/output/software_renderer.h"
 #include "cc/resources/resource_provider.h"
 #include "cc/test/paths.h"
 #include "cc/test/pixel_test_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gl/gl_implementation.h"
 #include "webkit/gpu/context_provider_in_process.h"
@@ skipping 35 matching lines @@
 
 PixelTest::PixelTest()
     : device_viewport_size_(gfx::Size(200, 200)),
       fake_client_(new PixelTestRendererClient(device_viewport_size_)) {}
 
 PixelTest::~PixelTest() {}
 
 bool PixelTest::RunPixelTest(RenderPassList* pass_list,
                              const base::FilePath& ref_file,
                              const PixelComparator& comparator) {
+  base::RunLoop run_loop;
+
   pass_list->back()->copy_callbacks.push_back(
-      base::Bind(&PixelTest::ReadbackResult, base::Unretained(this)));
+      base::Bind(&PixelTest::ReadbackResult,
+                 base::Unretained(this),
+                 run_loop.QuitClosure()));
 
   renderer_->DecideRenderPassAllocationsForFrame(*pass_list);
   renderer_->DrawFrame(pass_list);
 
-  // TODO(danakj): When the glReadPixels is async, wait for it to finish.
+  // Wait for the readback to complete.
+  resource_provider_->Finish();
+  run_loop.Run();
 
   return PixelsMatchReference(ref_file, comparator);
 }
 
-void PixelTest::ReadbackResult(scoped_ptr<SkBitmap> bitmap) {
+void PixelTest::ReadbackResult(base::Closure quit_run_loop,
+                               scoped_ptr<SkBitmap> bitmap) {
   result_bitmap_ = bitmap.Pass();
+  quit_run_loop.Run();
 }
 
 bool PixelTest::PixelsMatchReference(const base::FilePath& ref_file,
                                      const PixelComparator& comparator) {
   base::FilePath test_data_dir;
   if (!PathService::Get(cc::DIR_TEST_DATA, &test_data_dir))
     return false;
 
   // If this is false, we didn't set up a readback on a render pass.
   if (!result_bitmap_)
@@ skipping 35 matching lines @@
   scoped_ptr<SoftwareOutputDevice> device(new SoftwareOutputDevice());
   output_surface_.reset(new OutputSurface(device.Pass()));
   resource_provider_ = ResourceProvider::Create(output_surface_.get(), 0);
   renderer_ = SoftwareRenderer::Create(
       fake_client_.get(),
       output_surface_.get(),
       resource_provider_.get()).PassAs<DirectRenderer>();
 }
 
 }  // namespace cc