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

Source/core/html/track/vtt/VTTScanner.h

Index: Source/core/html/track/vtt/VTTScanner.h
diff --git a/Source/core/html/track/vtt/VTTScanner.h b/Source/core/html/track/vtt/VTTScanner.h
index 1d6411706bf4e704b793209400ee19e2dd102725..77a8e07a3472ddebb7f1fae90b7ba0b4197e559f 100644
--- a/Source/core/html/track/vtt/VTTScanner.h
+++ b/Source/core/html/track/vtt/VTTScanner.h
@@ -32,6 +32,7 @@
 
 #include "core/CoreExport.h"
 #include "platform/ParsingUtilities.h"
+#include "wtf/Allocator.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
@@ -48,6 +49,7 @@ namespace blink {
 // The 'scan' operation performs a 'match', and if the match is successful it
 // advance the input pointer past the matched sequence.
 class CORE_EXPORT VTTScanner {
+    STACK_ALLOCATED();
     WTF_MAKE_NONCOPYABLE(VTTScanner);
 public:
     explicit VTTScanner(const String& line);
@@ -55,6 +57,7 @@ public:
     typedef const LChar* Position;
 
     class Run {
+        STACK_ALLOCATED();
     public:
         Run(Position start, Position end, bool is8Bit)
             : m_start(start), m_end(end), m_is8Bit(is8Bit) { }