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

Source/core/paint/ObjectPainter.h

Index: Source/core/paint/ObjectPainter.h
diff --git a/Source/core/paint/ObjectPainter.h b/Source/core/paint/ObjectPainter.h
index 555e3161f2ac7e0cac960b9949b1669a5f605636..3944c3eb4f2b07f71b8352a88da061240c9b454f 100644
--- a/Source/core/paint/ObjectPainter.h
+++ b/Source/core/paint/ObjectPainter.h
@@ -6,6 +6,7 @@
 #define ObjectPainter_h
 
 #include "core/style/ComputedStyleConstants.h"
+#include "wtf/Allocator.h"
 #include "wtf/Vector.h"
 
 namespace blink {
@@ -19,6 +20,7 @@ class LayoutObject;
 class ComputedStyle;
 
 class ObjectPainter {
+    STACK_ALLOCATED();
 public:
     ObjectPainter(LayoutObject& layoutObject) : m_layoutObject(layoutObject) { }