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

Source/core/paint/BlockFlowPainter.h

Index: Source/core/paint/BlockFlowPainter.h
diff --git a/Source/core/paint/BlockFlowPainter.h b/Source/core/paint/BlockFlowPainter.h
index 4086b7a3080bb8eaba75e7c4d8cbeac1384d2a26..362724813af16d218d7f58aff5edef298f95ed5e 100644
--- a/Source/core/paint/BlockFlowPainter.h
+++ b/Source/core/paint/BlockFlowPainter.h
@@ -5,6 +5,8 @@
 #ifndef BlockFlowPainter_h
 #define BlockFlowPainter_h
 
+#include "wtf/Allocator.h"
+
 namespace blink {
 
 class LayoutPoint;
@@ -12,6 +14,7 @@ struct PaintInfo;
 class LayoutBlockFlow;
 
 class BlockFlowPainter {
+    STACK_ALLOCATED();
 public:
     BlockFlowPainter(LayoutBlockFlow& layoutBlockFlow) : m_layoutBlockFlow(layoutBlockFlow) { }
     void paintFloats(const PaintInfo&, const LayoutPoint&, bool preservePhase);