Web Inspector: count DOM storage cache memory for native snapshot

webkit/dom_storage/dom_storage_cached_area.h

Index: webkit/dom_storage/dom_storage_cached_area.h
diff --git a/webkit/dom_storage/dom_storage_cached_area.h b/webkit/dom_storage/dom_storage_cached_area.h
index fb6df402a2a9c1e15b3fef1cbe8bf17e968135f6..fc1968ed30f6f1f250944ec86c5bdd5ae6f76089 100644
--- a/webkit/dom_storage/dom_storage_cached_area.h
+++ b/webkit/dom_storage/dom_storage_cached_area.h
@@ -18,7 +18,7 @@ class DomStorageMap;
 class DomStorageProxy;
 
 // Unlike the other classes in the dom_storage library, this one is intended
-// for use in renderer processes. It maintains a complete cach of the an
+// for use in renderer processes. It maintains a complete cache of the
 // origin's Map of key/value pairs for fast access. The cache is primed on
 // first access and changes are written to the backend thru the |proxy|.
 // Mutations originating in other processes are applied to the cache via
@@ -43,6 +43,8 @@ class DomStorageCachedArea : public base::RefCounted<DomStorageCachedArea> {
   void ApplyMutation(const NullableString16& key,
                      const NullableString16& new_value);
 
+  size_t MemoryBytesUsedByCache() const;
+
  private:
   friend class DomStorageCachedAreaTest;
   friend class base::RefCounted<DomStorageCachedArea>;