Fix cpplint errors in cc/(animation|input|layers|trees|test)/

cc/test/fake_layer_tree_host_client.h

 // 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.
 
 #ifndef CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_
 #define CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/input/input_handler.h"
 #include "cc/test/fake_context_provider.h"
 #include "cc/test/fake_output_surface.h"
 #include "cc/trees/layer_tree_host.h"
 
 namespace cc {
 
 class FakeLayerTreeHostClient : public LayerTreeHostClient {
  public:
   enum RendererOptions {
     DIRECT_3D,
     DIRECT_SOFTWARE,
     DELEGATED_3D,
     DELEGATED_SOFTWARE
   };
-  FakeLayerTreeHostClient(RendererOptions options);
+  explicit FakeLayerTreeHostClient(RendererOptions options);
   virtual ~FakeLayerTreeHostClient();
 
   virtual void WillBeginFrame() OVERRIDE {}
   virtual void DidBeginFrame() OVERRIDE {}
   virtual void Animate(double frame_begin_time) OVERRIDE {}
   virtual void Layout() OVERRIDE {}
   virtual void ApplyScrollAndScale(gfx::Vector2d scroll_delta,
                                    float page_scale) OVERRIDE {}
 
   virtual scoped_ptr<OutputSurface> CreateOutputSurface() OVERRIDE;
@@ skipping 16 matching lines @@
   bool use_software_rendering_;
   bool use_delegating_renderer_;
 
   scoped_refptr<FakeContextProvider> main_thread_contexts_;
   scoped_refptr<FakeContextProvider> compositor_thread_contexts_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_LAYER_TREE_HOST_CLIENT_H_