CSSValue Immediates: Replace CSSPrimitiveValue usage with const references

Source/core/animation/LengthBoxStyleInterpolation.cpp

 // 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.
 
 #include "config.h"
 #include "core/animation/LengthBoxStyleInterpolation.h"
 
 #include "core/css/resolver/StyleBuilder.h"
 
 namespace blink {
@@ skipping 38 matching lines @@
             result->set(i, LengthStyleInterpolation::toInterpolableValue(sideCSSValue));
         }
     }
     return result.release();
 }
 
 bool LengthBoxStyleInterpolation::usesDefaultInterpolation(const CSSValue& start, const CSSValue& end)
 {
     if (!start.isPrimitiveValue() || !end.isPrimitiveValue())
         return false;
-    const CSSPrimitiveValue startValue = toCSSPrimitiveValue(start);
-    const CSSPrimitiveValue endValue = toCSSPrimitiveValue(end);
+    const CSSPrimitiveValue& startValue = toCSSPrimitiveValue(start);
+    const CSSPrimitiveValue& endValue = toCSSPrimitiveValue(end);
     if ((startValue.isValueID() && startValue.getValueID() == CSSValueAuto)
         || (endValue.isValueID() && endValue.getValueID() == CSSValueAuto))
         return true;
     return onlyInterpolateBetweenLengthAndCSSValueAuto(*startValue.getRectValue(), *endValue.getRectValue());
 }
 
 namespace {
 
 CSSPrimitiveValue indexedValueToLength(InterpolableList& lengthBox, size_t i, CSSPrimitiveValue start[], CSSPrimitiveValue end[])
 {
@@ skipping 33 matching lines @@
 }
 
 DEFINE_TRACE(LengthBoxStyleInterpolation)
 {
     StyleInterpolation::trace(visitor);
     visitor->trace(m_startCSSValue);
     visitor->trace(m_endCSSValue);
 }
 
 }