Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/loader/resource/CSSStyleSheetResource.cpp

Index: third_party/WebKit/Source/core/loader/resource/CSSStyleSheetResource.cpp
diff --git a/third_party/WebKit/Source/core/loader/resource/CSSStyleSheetResource.cpp b/third_party/WebKit/Source/core/loader/resource/CSSStyleSheetResource.cpp
index 41dea66b4356d384e1a6e69a1ae06e87d179a913..fe50b21052313bee96b49dd132e7ae349d8dd718 100644
--- a/third_party/WebKit/Source/core/loader/resource/CSSStyleSheetResource.cpp
+++ b/third_party/WebKit/Source/core/loader/resource/CSSStyleSheetResource.cpp
@@ -186,7 +186,7 @@ bool CSSStyleSheetResource::canUseSheet(MIMETypeCheck mimeTypeCheck) const {
 }
 
 StyleSheetContents* CSSStyleSheetResource::restoreParsedStyleSheet(
-    const CSSParserContext& context) {
+    const CSSParserContext* context) {
   if (!m_parsedStyleSheetCache)
     return nullptr;
   if (m_parsedStyleSheetCache->hasFailedOrCanceledSubresources()) {
@@ -199,7 +199,7 @@ StyleSheetContents* CSSStyleSheetResource::restoreParsedStyleSheet(
 
   // Contexts must be identical so we know we would get the same exact result if
   // we parsed again.
-  if (m_parsedStyleSheetCache->parserContext() != context)
+  if (*m_parsedStyleSheetCache->parserContext() != *context)
     return nullptr;
 
   return m_parsedStyleSheetCache;