cc: Convert non-const reference arguments to pointers.

cc/animation/transform_operation.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_ANIMATION_TRANSFORM_OPERATION_H_
 #define CC_ANIMATION_TRANSFORM_OPERATION_H_
 
 #include "ui/gfx/transform.h"
 
 namespace cc {
@@ skipping 37 matching lines @@
       } axis;
 
       double angle;
     } rotate;
   };
 
   bool IsIdentity() const;
   static bool BlendTransformOperations(const TransformOperation* from,
                                        const TransformOperation* to,
                                        double progress,
-                                       gfx::Transform& result);
+                                       gfx::Transform* result);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_TRANSFORM_OPERATION_H_