Add option --dump-render-tree to content_shell to dump the render tree as text.

BUG=111316
TEST=run out/Debug/content_shell --dump-render-tree file://$(pwd)/third_party/WebKit/LayoutTests/fast/html/section-element.html > section-element-actual.txt - should be the same as section-element-expected.txt


Review URL: http://codereview.chromium.org/9289045

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@119642 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: efb5f5799f2c3aab8c3ddf3558320b7c3d587c99
diff --git a/ipc/ipc_message_utils.h b/ipc/ipc_message_utils.h
index 5176847..9d750ca 100644
--- a/ipc/ipc_message_utils.h
+++ b/ipc/ipc_message_utils.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -98,6 +98,7 @@
   IntentsMsgStart,
   JavaBridgeMsgStart,
   GamepadMsgStart,
+  ShellMsgStart,
   LastIPCMsgStart      // Must come last.
 };