Make classes and structures in core/dom fast-allocated.

Source/core/dom/StyleChangeReason.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 StyleChangeReason_h
 #define StyleChangeReason_h
 
 #include "core/dom/QualifiedName.h"
 #include "wtf/NullPtr.h"
 #include "wtf/PassRefPtr.h"
@@ skipping 50 matching lines @@
 
 void init();
 }
 
 // |StyleChangeReasonForTracing| is used to trace the reason a
 // |Node::setNeedsStyleRecalc| call was made to show it in DevTools or in
 // about:tracing.
 // |StyleChangeReasonForTracing| is strictly only for the tracing purpose as
 // described above. Blink logic must not depend on this value.
 class StyleChangeReasonForTracing {
+    DISALLOW_ALLOCATION();
 public:
     static StyleChangeReasonForTracing create(StyleChangeReasonString reasonString)
     {
         return StyleChangeReasonForTracing(reasonString, nullAtom);
     }
 
     static StyleChangeReasonForTracing createWithExtraData(StyleChangeReasonString reasonString, const AtomicString& extraData)
     {
         return StyleChangeReasonForTracing(reasonString, extraData);
     }
@@ skipping 17 matching lines @@
     void operator==(const StyleChangeReasonForTracing&) const { }
     void operator!=(const StyleChangeReasonForTracing&) const { }
 
     const char* m_reason;
     AtomicString m_extraData;
 };
 
 } // namespace blink
 
 #endif // StyleChangeReason_h