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

Source/web/tests/mocks/MockLayerTreeView.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 "web/tests/mocks/MockLayerTreeView.h"
+
+#include "public/platform/Platform.h"
+#include "public/platform/WebUnitTestSupport.h"
+
+namespace blink {
+
+MockLayerTreeView::MockLayerTreeView()
+    : m_layerTreeView(adoptPtr(Platform::current()->unitTestSupport()->createLayerTreeViewForTesting()))
+    , m_needsAnimate(false)
+    , m_deferCommits(true)
+{
+    ASSERT(m_layerTreeView);
+}
+
+} // namespace blink