Make classes and structures in web fast-allocated.

Source/web/painting/PaintAggregator.h

Index: Source/web/painting/PaintAggregator.h
diff --git a/Source/web/painting/PaintAggregator.h b/Source/web/painting/PaintAggregator.h
index ab0c3cbe34abbb0106392bd0c47ff77cb1b8c173..28c2cab888283729d90be07be9f0a3da6ecfa817 100644
--- a/Source/web/painting/PaintAggregator.h
+++ b/Source/web/painting/PaintAggregator.h
@@ -33,6 +33,7 @@
 
 #include "platform/geometry/IntPoint.h"
 #include "platform/geometry/IntRect.h"
+#include "wtf/Allocator.h"
 #include "wtf/Vector.h"
 
 namespace blink {
@@ -40,6 +41,7 @@ namespace blink {
 // This class is responsible for aggregating multiple invalidation and scroll
 // commands to produce a scroll and repaint sequence.
 class PaintAggregator {
+    STACK_ALLOCATED();
 public:
     // This structure describes an aggregation of invalidateRect and scrollRect
     // calls. If |scrollRect| is non-empty, then that rect should be scrolled
@@ -49,6 +51,7 @@ public:
     // |scrollDelta| can only specify scrolling in one direction (i.e., the x
     // and y members cannot both be non-zero).
     struct PendingUpdate {
+        STACK_ALLOCATED();
         PendingUpdate();
         ~PendingUpdate();