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

Source/core/page/scrolling/ScrollingConstraints.h

Index: Source/core/page/scrolling/ScrollingConstraints.h
diff --git a/Source/core/page/scrolling/ScrollingConstraints.h b/Source/core/page/scrolling/ScrollingConstraints.h
index cb40ad4ce75feeb75d9b31364cd2ba1fb46a652f..6b3dca6ed15f4f13cb52653d392476c18f874ecc 100644
--- a/Source/core/page/scrolling/ScrollingConstraints.h
+++ b/Source/core/page/scrolling/ScrollingConstraints.h
@@ -27,12 +27,14 @@
 #define ScrollingConstraints_h
 
 #include "platform/geometry/FloatRect.h"
+#include "wtf/Allocator.h"
 
 namespace blink {
 
 // ViewportConstraints classes encapsulate data and logic required to reposition elements whose layout
 // depends on the viewport rect (i.e., position fixed), when scrolling and zooming.
 class ViewportConstraints {
+    STACK_ALLOCATED();
 public:
     // FIXME: Simplify this code now that position: sticky doesn't exist.
     enum ConstraintType {
@@ -74,6 +76,7 @@ protected:
 };
 
 class FixedPositionViewportConstraints final : public ViewportConstraints {
+    STACK_ALLOCATED();
 public:
     FixedPositionViewportConstraints()
         : ViewportConstraints()