Make blink classes and structures in core/css fast-allocated

Source/core/css/parser/MediaQueryBlockWatcher.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MediaQueryBlockWatcher_h
 #define MediaQueryBlockWatcher_h
 
 #include "core/CoreExport.h"
+#include "wtf/Allocator.h"
 
 namespace blink {
 
 class CSSParserToken;
 
 class CORE_EXPORT MediaQueryBlockWatcher {
+    STACK_ALLOCATED();
 public:
-
     MediaQueryBlockWatcher();
     void handleToken(const CSSParserToken&);
     unsigned blockLevel() const { return m_blockLevel; }
 
 private:
     unsigned m_blockLevel;
 };
 
 } // namespace
 
 #endif // MediaQueryBlockWatcher_h