Make CSSParserContext be garbage collected.

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

Index: third_party/WebKit/Source/core/css/ActiveStyleSheetsTest.cpp
diff --git a/third_party/WebKit/Source/core/css/ActiveStyleSheetsTest.cpp b/third_party/WebKit/Source/core/css/ActiveStyleSheetsTest.cpp
index e22465a47af3244bd13fecf72073298873e17a02..1cd52d06d0b5a4b10a4d9b6a833a7c7a20bfb4af 100644
--- a/third_party/WebKit/Source/core/css/ActiveStyleSheetsTest.cpp
+++ b/third_party/WebKit/Source/core/css/ActiveStyleSheetsTest.cpp
@@ -23,7 +23,7 @@ class ActiveStyleSheetsTest : public ::testing::Test {
  protected:
   static CSSStyleSheet* createSheet(const String& cssText = String()) {
     StyleSheetContents* contents =
-        StyleSheetContents::create(CSSParserContext(HTMLStandardMode, nullptr));
+        StyleSheetContents::create(CSSParserContext::create(HTMLStandardMode));
     contents->parseString(cssText);
     contents->ensureRuleSet(MediaQueryEvaluator(),
                             RuleHasDocumentSecurityOrigin);