Purge in-memory localStorage areas if the # of areas exceeds the limit

content/common/dom_storage_messages.h

Index: content/common/dom_storage_messages.h
diff --git a/content/common/dom_storage_messages.h b/content/common/dom_storage_messages.h
index c132a1cc468009a8c5fbfa44a80b78a5ecd3ed5f..2e51ea2dcc9c7412b9bf37824d43c43859675b38 100644
--- a/content/common/dom_storage_messages.h
+++ b/content/common/dom_storage_messages.h
@@ -36,6 +36,8 @@ IPC_STRUCT_BEGIN(DOMStorageMsg_Event_Params)
   // The non-zero session namespace_id associated with the event or 0 if
   // this is a local storage event.
   IPC_STRUCT_MEMBER(int64, namespace_id)
+
+  IPC_STRUCT_MEMBER(int64, storage_size)
 IPC_STRUCT_END()
 
 IPC_ENUM_TRAITS(WebKit::WebStorageArea::Result)
@@ -56,10 +58,11 @@ IPC_MESSAGE_CONTROL1(DOMStorageMsg_AsyncOperationComplete,
 // Note: The 'connection_id' must be the first parameter in these message.
 
 // Open the storage area for a particular origin within a namespace.
-IPC_MESSAGE_CONTROL3(DOMStorageHostMsg_OpenStorageArea,
-                     int /* connection_id */,
-                     int64 /* namespace_id */,
-                     GURL /* origin */)
+IPC_SYNC_MESSAGE_CONTROL3_1(DOMStorageHostMsg_OpenStorageArea,
+                            int /* connection_id */,
+                            int64 /* namespace_id */,
+                            GURL /* origin */,
+                            int64 /* storage_size (out) */)
 
 // Close a previously opened storage area.
 IPC_MESSAGE_CONTROL1(DOMStorageHostMsg_CloseStorageArea,