Change StyleResolverState.styleImage() to take a const CSSValue&

third_party/WebKit/Source/core/style/StylePendingImage.h

 /*
  * Copyright (C) 2010 Apple Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
 #include "platform/graphics/Image.h"
 
 namespace blink {
 
 // StylePendingImage is a placeholder StyleImage that is entered into the ComputedStyle during
 // style resolution, in order to avoid loading images that are not referenced by the final style.
 // They should never exist in a ComputedStyle after it has been returned from the style selector.
 
 class StylePendingImage final : public StyleImage {
 public:
-    static PassRefPtrWillBeRawPtr<StylePendingImage> create(CSSValue* value)
+    static PassRefPtrWillBeRawPtr<StylePendingImage> create(const CSSValue& value)

[alancutter (OOO until 2018), 2015/10/07 03:28:28]

I don't think we should break the pattern of create() methods taking
PassRefPtrs. I would prefer to see the const_cast at the call sites to create().
I expect one day we will have create(PassRefPtr<const CSSValue>).

     {
         return adoptRefWillBeNoop(new StylePendingImage(value));
     }
 
     WrappedImagePtr data() const override { return m_value.get(); }
 
     PassRefPtrWillBeRawPtr<CSSValue> cssValue() const override { return m_value; }
 
     PassRefPtrWillBeRawPtr<CSSValue> computedCSSValue() const override
     {
@@ skipping 21 matching lines @@
     }
     bool knownToBeOpaque(const LayoutObject*) const override { return false; }
 
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
         visitor->trace(m_value);
         StyleImage::trace(visitor);
     }
 
 private:
-    explicit StylePendingImage(CSSValue* value)
-        : m_value(value)
+    explicit StylePendingImage(const CSSValue& value)
+        : m_value(const_cast<CSSValue*>(&value))
     {
         m_isPendingImage = true;
     }
 
+    // TODO(sashab): Replace this with <const CSSValue> once RefPtrWillBeMember<>
+    // supports const types.
     RefPtrWillBeMember<CSSValue> m_value;
 };
 
 DEFINE_STYLE_IMAGE_TYPE_CASTS(StylePendingImage, isPendingImage());
 
 }
 #endif