Make CSSValuePair store const CSSValues

third_party/WebKit/Source/core/css/CSSBasicShapeValues.cpp

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 53 matching lines @@
 {
     if ((toCSSPrimitiveValue(offset.first()).getValueID() == CSSValueLeft && toCSSPrimitiveValue(other.first()).getValueID() == CSSValueTop)
         || (toCSSPrimitiveValue(offset.first()).getValueID() == CSSValueTop && toCSSPrimitiveValue(other.first()).getValueID() == CSSValueLeft))
         return offset.second().cssText();
     return offset.cssText();
 }
 
 static CSSValuePair* buildSerializablePositionOffset(CSSValue* offset, CSSValueID defaultSide)
 {
     CSSValueID side = defaultSide;
-    CSSPrimitiveValue* amount = nullptr;
+    const CSSPrimitiveValue* amount = nullptr;
 
     if (!offset) {
         side = CSSValueCenter;
     } else if (offset->isPrimitiveValue() && toCSSPrimitiveValue(offset)->isValueID()) {
         side = toCSSPrimitiveValue(offset)->getValueID();
     } else if (offset->isValuePair()) {
         side = toCSSPrimitiveValue(toCSSValuePair(*offset).first()).getValueID();
         amount = &toCSSPrimitiveValue(toCSSValuePair(*offset).second());
         if ((side == CSSValueRight || side == CSSValueBottom) && amount->isPercentage()) {
             side = defaultSide;
@@ skipping 313 matching lines @@
     visitor->trace(m_left);
     visitor->trace(m_topLeftRadius);
     visitor->trace(m_topRightRadius);
     visitor->trace(m_bottomRightRadius);
     visitor->trace(m_bottomLeftRadius);
     CSSValue::traceAfterDispatch(visitor);
 }
 
 } // namespace blink