Add a test that we resume commits after inserting the body.

Source/web/tests/mocks/MockWebViewClient.cpp

 // Copyright 2015 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.
 
 #include "config.h"
-#include "modules/mediasession/MediaSession.h"
+#include "web/tests/mocks/MockWebViewClient.h"
+
+#include "public/platform/WebLayerTreeView.h"
 
 namespace blink {
 
-MediaSession* MediaSession::create()
-{
-    return new MediaSession;
-}
-
-void MediaSession::activate()
+MockWebViewClient::MockWebViewClient(WebLayerTreeView& layerTreeView)
+    : m_layerTreeView(&layerTreeView)
 {
 }
 
-void MediaSession::deactivate()
-{
-}
-
 } // namespace blink