DomStorageCachedArea + DomStorageProxy interface and unittests. These classes aren't used yet.

webkit/dom_storage/dom_storage_map.h

Index: webkit/dom_storage/dom_storage_map.h
===================================================================
--- webkit/dom_storage/dom_storage_map.h	(revision 138339)
+++ webkit/dom_storage/dom_storage_map.h	(working copy)
@@ -21,7 +21,7 @@
 class DomStorageMap
     : public base::RefCountedThreadSafe<DomStorageMap> {
  public:
-  DomStorageMap(size_t quota);
+  explicit DomStorageMap(size_t quota);
 
   unsigned Length() const;
   NullableString16 Key(unsigned index);
@@ -43,6 +43,8 @@
   DomStorageMap* DeepCopy() const;
 
   size_t bytes_used() const { return bytes_used_; }
+  size_t quota() const { return quota_; }
+  void set_quota(size_t quota) { quota_ = quota; }
 
  private:
   friend class base::RefCountedThreadSafe<DomStorageMap>;