Fix unused variables errors in cc/.

cc/test/animation_timelines_test_common.h

 // Copyright 2015 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_TIMELINES_TEST_COMMON_H_
 #define CC_TEST_ANIMATION_TIMELINES_TEST_COMMON_H_
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/animation/animation.h"
@@ skipping 50 matching lines @@
 
   float opacity_;
   float brightness_;
   gfx::ScrollOffset scroll_offset_;
 
   bool mutated_properties_[Animation::LAST_TARGET_PROPERTY + 1];
 };
 
 class TestHostClient : public MutatorHostClient {
  public:
-  explicit TestHostClient(ThreadInstance thread_instance);
+  TestHostClient();
   ~TestHostClient();
 
   void ClearMutatedProperties();
 
   bool IsLayerInTree(int layer_id, LayerTreeType tree_type) const override;
 
   void SetMutatorsNeedCommit() override;
 
   void SetLayerFilterMutated(int layer_id,
                              LayerTreeType tree_type,
@@ skipping 99 matching lines @@
   scoped_refptr<AnimationTimeline> timeline_;
   scoped_refptr<AnimationPlayer> player_;
 
   scoped_refptr<AnimationTimeline> timeline_impl_;
   scoped_refptr<AnimationPlayer> player_impl_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_ANIMATION_TIMELINES_TEST_COMMON_H_