Mac: Don't repaint scrollbars every frame

cc/test/fake_layer_tree_host.h

 // 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.
 
 #ifndef CC_TEST_FAKE_LAYER_TREE_HOST_H_
 #define CC_TEST_FAKE_LAYER_TREE_HOST_H_
 
 #include "cc/debug/micro_benchmark_controller.h"
 #include "cc/test/fake_impl_task_runner_provider.h"
 #include "cc/test/fake_layer_tree_host_client.h"
@@ skipping 11 matching lines @@
   static scoped_ptr<FakeLayerTreeHost> Create(
       FakeLayerTreeHostClient* client,
       TestTaskGraphRunner* task_graph_runner);
   static scoped_ptr<FakeLayerTreeHost> Create(
       FakeLayerTreeHostClient* client,
       TestTaskGraphRunner* task_graph_runner,
       const LayerTreeSettings& settings);
 
   ~FakeLayerTreeHost() override;
 
+  const RendererCapabilities& GetRendererCapabilities() const override;
   void SetNeedsCommit() override;
   void SetNeedsUpdateLayers() override {}
   void SetNeedsFullTreeSync() override {}
 
   using LayerTreeHost::SetRootLayer;
   using LayerTreeHost::root_layer;
 
   LayerImpl* CommitAndCreateLayerImplTree();
 
   FakeLayerTreeHostImpl* host_impl() { return &host_impl_; }
   LayerTreeImpl* active_tree() { return host_impl_.active_tree(); }
 
   using LayerTreeHost::ScheduleMicroBenchmark;
   using LayerTreeHost::SendMessageToMicroBenchmark;
   using LayerTreeHost::SetOutputSurfaceLostForTesting;
   using LayerTreeHost::InitializeSingleThreaded;
   using LayerTreeHost::InitializeForTesting;
   void UpdateLayers() { LayerTreeHost::UpdateLayers(); }
 
   MicroBenchmarkController* GetMicroBenchmarkController() {
     return &micro_benchmark_controller_;
   }
 
   bool needs_commit() { return needs_commit_; }
 
+  void set_renderer_capabilities(const RendererCapabilities& capabilities) {
+    renderer_capabilities_set = true;
+    renderer_capabilities = capabilities;
+  }
+
  protected:
   FakeLayerTreeHost(FakeLayerTreeHostClient* client,
                     LayerTreeHost::InitParams* params);
 
  private:
   FakeImplTaskRunnerProvider task_runner_provider_;
   FakeLayerTreeHostClient* client_;
   TestSharedBitmapManager manager_;
   FakeLayerTreeHostImpl host_impl_;
   bool needs_commit_;
+
+  bool renderer_capabilities_set;
+  RendererCapabilities renderer_capabilities;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_LAYER_TREE_HOST_H_