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

Source/core/paint/LineBoxListPainter.h

Index: Source/core/paint/LineBoxListPainter.h
diff --git a/Source/core/paint/LineBoxListPainter.h b/Source/core/paint/LineBoxListPainter.h
index 367cc08e66d0d81921a3b70a15da03498e5a0b8c..e6f9397fd0d621fc68e6e88d78c548dd992ad3e3 100644
--- a/Source/core/paint/LineBoxListPainter.h
+++ b/Source/core/paint/LineBoxListPainter.h
@@ -6,6 +6,7 @@
 #define LineBoxListPainter_h
 
 #include "core/style/ComputedStyleConstants.h"
+#include "wtf/Allocator.h"
 
 namespace blink {
 
@@ -15,6 +16,7 @@ class LayoutBoxModelObject;
 class LineBoxList;
 
 class LineBoxListPainter {
+    STACK_ALLOCATED();
 public:
     LineBoxListPainter(LineBoxList& lineBoxList) : m_lineBoxList(lineBoxList) { }