[part 1] Make classes and structures in modules/ fast-allocated.

Source/modules/filesystem/DOMFilePath.h

Index: Source/modules/filesystem/DOMFilePath.h
diff --git a/Source/modules/filesystem/DOMFilePath.h b/Source/modules/filesystem/DOMFilePath.h
index 92a9f5fa153a85f8b48f74532290742e69b4c743..2bc1a525c48085aab189ddb05e5c0b75fc9be146 100644
--- a/Source/modules/filesystem/DOMFilePath.h
+++ b/Source/modules/filesystem/DOMFilePath.h
@@ -31,12 +31,14 @@
 #ifndef DOMFilePath_h
 #define DOMFilePath_h
 
+#include "wtf/Allocator.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 // DOMFileSystem path utilities. All methods in this class are static.
 class DOMFilePath {
+    STATIC_ONLY(DOMFilePath);
 public:
     static const char separator;
     static const char root[];
@@ -74,9 +76,6 @@ public:
 
     // Checks if the given name follows the FileSystem API naming restrictions.
     static bool isValidName(const String& name);
-
-private:
-    DOMFilePath() { }
 };
 
 } // namespace blink