Make PropertyHandle instances const references where possible

third_party/WebKit/Source/core/animation/InterpolationEffect.h

 // Copyright 2014 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 InterpolationEffect_h
 #define InterpolationEffect_h
 
 #include "core/CoreExport.h"
 #include "core/animation/Interpolation.h"
 #include "core/animation/Keyframe.h"
@@ skipping 28 matching lines @@
                         double start,
                         double end,
                         double applyFrom,
                         double applyTo) {
     m_interpolations.push_back(InterpolationRecord(std::move(interpolation),
                                                    std::move(easing), start,
                                                    end, applyFrom, applyTo));
   }
 
   void addInterpolationsFromKeyframes(
-      PropertyHandle,
+      const PropertyHandle&,
       const Keyframe::PropertySpecificKeyframe& keyframeA,
       const Keyframe::PropertySpecificKeyframe& keyframeB,
       double applyFrom,
       double applyTo);
 
  private:
   struct InterpolationRecord {
     InterpolationRecord(PassRefPtr<Interpolation> interpolation,
                         PassRefPtr<TimingFunction> easing,
                         double start,
@@ skipping 15 matching lines @@
     double m_applyTo;
   };
 
   bool m_isPopulated;
   Vector<InterpolationRecord> m_interpolations;
 };
 
 }  // namespace blink
 
 #endif  // InterpolationEffect_h