Introduce all the plumbing for Session Storage. This mostly consists of crea...

chrome/common/dom_storage_common.h

Index: chrome/common/dom_storage_common.h
===================================================================
--- chrome/common/dom_storage_common.h	(revision 0)
+++ chrome/common/dom_storage_common.h	(revision 0)
@@ -0,0 +1,16 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.  Use of this
+// source code is governed by a BSD-style license that can be found in the
+// LICENSE file.
+
+#ifndef CHROME_COMMON_DOM_STORAGE_COMMON_H_
+#define CHROME_COMMON_DOM_STORAGE_COMMON_H_
+
+const int64 kLocalStorageNamespaceId = 0;
+const int64 kInvalidSessionStorageNamespaceId = kLocalStorageNamespaceId;
+
+enum DOMStorageType {
+  DOM_STORAGE_LOCAL = 0,
+  DOM_STORAGE_SESSION
+};
+
+#endif  // CHROME_COMMON_DOM_STORAGE_COMMON_H_