CSS: Drop the quirks-mode exception for CSS MIME types.

Source/core/css/StyleSheetContents.cpp

Index: Source/core/css/StyleSheetContents.cpp
diff --git a/Source/core/css/StyleSheetContents.cpp b/Source/core/css/StyleSheetContents.cpp
index 91fbc220e58a5385d596d0a6344ebb81adf76daa..1851d54797acf29b686ff85aa166aa4685f963c2 100644
--- a/Source/core/css/StyleSheetContents.cpp
+++ b/Source/core/css/StyleSheetContents.cpp
@@ -283,11 +283,8 @@ void StyleSheetContents::parseAuthorStyleSheet(const CSSStyleSheetResource* cach
     TRACE_EVENT0("blink", "StyleSheetContents::parseAuthorStyleSheet");
     TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "ParseAuthorStyleSheet", "data", InspectorParseAuthorStyleSheetEvent::data(cachedStyleSheet));
 
-    bool quirksMode = isQuirksModeBehavior(m_parserContext.mode());
-
-    bool enforceMIMEType = !quirksMode;
     bool hasValidMIMEType = false;
-    String sheetText = cachedStyleSheet->sheetText(enforceMIMEType, &hasValidMIMEType);
+    String sheetText = cachedStyleSheet->sheetText(&hasValidMIMEType);
 
     const ResourceResponse& response = cachedStyleSheet->response();
     m_sourceMapURL = response.httpHeaderField("SourceMap");