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

cc/test/animation_test_common.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_ANIMATION_TEST_COMMON_H_
 #define CC_TEST_ANIMATION_TEST_COMMON_H_
 
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_curve.h"
 #include "cc/animation/layer_animation_controller.h"
@@ skipping 15 matching lines @@
   virtual double Duration() const OVERRIDE;
   virtual float GetValue(double now) const OVERRIDE;
   virtual scoped_ptr<AnimationCurve> Clone() const OVERRIDE;
 
  private:
   double duration_;
 };
 
 class FakeTransformTransition : public TransformAnimationCurve {
  public:
-  FakeTransformTransition(double duration);
+  explicit FakeTransformTransition(double duration);
   virtual ~FakeTransformTransition();
 
   virtual double Duration() const OVERRIDE;
   virtual gfx::Transform GetValue(double time) const OVERRIDE;
 
   virtual scoped_ptr<AnimationCurve> Clone() const OVERRIDE;
 
  private:
   double duration_;
 };
@@ skipping 61 matching lines @@
                                 int delta_y);
 
 int AddAnimatedTransformToLayer(LayerImpl* layer,
                                 double duration,
                                 int delta_x,
                                 int delta_y);
 
 }  // namespace cc
 
 #endif  // CC_TEST_ANIMATION_TEST_COMMON_H_