[wip/exp] cc: Measure the amount of overdraw.

ash/test/ash_test_helper.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 "ash/test/ash_test_helper.h"
 
 #include <algorithm>
 #include <set>
 
 #include "ash/accelerators/accelerator_controller_delegate_aura.h"
@@ skipping 343 matching lines @@
   } else {
     int next_x = 0;
     CreateRootWindowController("800x600", &next_x);
   }
 }
 
 void AshTestHelper::CreateShell() {
   CHECK(config_ == Config::CLASSIC);
   ui::ContextFactory* context_factory = nullptr;
   ui::ContextFactoryPrivate* context_factory_private = nullptr;
-  bool enable_pixel_output = false;
+  bool enable_pixel_output = true;
   ui::InitializeContextFactoryForTests(enable_pixel_output, &context_factory,
                                        &context_factory_private);
   ShellInitParams init_params;
   init_params.delegate = test_shell_delegate_;
   init_params.context_factory = context_factory;
   init_params.context_factory_private = context_factory_private;
   init_params.blocking_pool = ash_test_environment_->GetBlockingPool();
   Shell::CreateInstance(init_params);
 }
 
@@ skipping 37 matching lines @@
   std::set<RootWindowController*> roots =
       window_manager_app_->window_manager()->GetRootWindowControllers();
   std::vector<RootWindowController*> ordered_roots;
   ordered_roots.insert(ordered_roots.begin(), roots.begin(), roots.end());
   std::sort(ordered_roots.begin(), ordered_roots.end(), &CompareByDisplayId);
   return ordered_roots;
 }
 
 }  // namespace test
 }  // namespace ash