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

Source/core/paint/VideoPainter.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 VideoPainter_h
 #define VideoPainter_h
 
+#include "wtf/Allocator.h"
+
 namespace blink {
 
 struct PaintInfo;
 class LayoutPoint;
 class LayoutVideo;
 
 class VideoPainter {
+    STACK_ALLOCATED();
 public:
     VideoPainter(LayoutVideo& layoutVideo) : m_layoutVideo(layoutVideo) { }
 
     void paintReplaced(const PaintInfo&, const LayoutPoint&);
 
 private:
 
     LayoutVideo& m_layoutVideo;
 };
 
 } // namespace blink
 
 #endif // VideoPainter_h