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

Source/web/tests/mocks/MockWebViewClient.cpp

Index: Source/web/tests/mocks/MockWebViewClient.cpp
diff --git a/Source/modules/mediasession/MediaSession.cpp b/Source/web/tests/mocks/MockWebViewClient.cpp
similarity index 53%
copy from Source/modules/mediasession/MediaSession.cpp
copy to Source/web/tests/mocks/MockWebViewClient.cpp
index 937bf7f19d23f26aadf5c3f1ae0393ae0050d093..2fb3dd43af79c4172cd246bd0a79c6f12678c03a 100644
--- a/Source/modules/mediasession/MediaSession.cpp
+++ b/Source/web/tests/mocks/MockWebViewClient.cpp
@@ -3,20 +3,14 @@
 // found in the LICENSE file.
 
 #include "config.h"
-#include "modules/mediasession/MediaSession.h"
+#include "web/tests/mocks/MockWebViewClient.h"
 
-namespace blink {
-
-MediaSession* MediaSession::create()
-{
-    return new MediaSession;
-}
+#include "public/platform/WebLayerTreeView.h"
 
-void MediaSession::activate()
-{
-}
+namespace blink {
 
-void MediaSession::deactivate()
+MockWebViewClient::MockWebViewClient(WebLayerTreeView& layerTreeView)
+    : m_layerTreeView(&layerTreeView)
 {
 }