Oilpan: Fix build after r180164.

Source/core/inspector/InspectorStyleSheet.cpp

Index: Source/core/inspector/InspectorStyleSheet.cpp
diff --git a/Source/core/inspector/InspectorStyleSheet.cpp b/Source/core/inspector/InspectorStyleSheet.cpp
index dbe5118c5e5d708769ac405a0d4d88cbe54be2ba..59438fcfff4e281a5fc906f459fc812a528bb463 100644
--- a/Source/core/inspector/InspectorStyleSheet.cpp
+++ b/Source/core/inspector/InspectorStyleSheet.cpp
@@ -1127,7 +1127,6 @@ CSSStyleRule* InspectorStyleSheet::insertCSSOMRuleBySourceRange(const SourceRang
 bool InspectorStyleSheet::verifyRuleText(const String& ruleText)
 {
     DEFINE_STATIC_LOCAL(String, bogusPropertyName, ("-webkit-boguz-propertee"));
-    RefPtrWillBeRawPtr<MutableStylePropertySet> tempMutableStyle = MutableStylePropertySet::create();
     RuleSourceDataList sourceData;
     RefPtrWillBeRawPtr<StyleSheetContents> styleSheetContents = StyleSheetContents::create(strictCSSParserContext());
     String text = ruleText + " div { " + bogusPropertyName + ": none; }";