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

Source/core/layout/compositing/CompositedSelectionBound.h

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef CompositedSelectionBound_h
 #define CompositedSelectionBound_h
 
 #include "platform/geometry/FloatPoint.h"
 #include "platform/graphics/GraphicsLayer.h"
+#include "wtf/Allocator.h"
 
 namespace blink {
 
 struct CompositedSelectionBound {
+    STACK_ALLOCATED();
     CompositedSelectionBound()
         : layer(nullptr)
         , isTextDirectionRTL(false)
     {
     }
 
     // The structure describes the position of a caret in space of the GraphicsLayer the caret resides in.
     // Where edgeTopInLayer is the top point of the caret, usually on the ascend line of the line box,
     // and edgeBottomInLayer it the bottom point, on the baseline of the line box.
     GraphicsLayer* layer;
     FloatPoint edgeTopInLayer;
     FloatPoint edgeBottomInLayer;
 
     bool isTextDirectionRTL;
 };
 
 } // namespace blink
 
 #endif