[DevTools] Make sendMessageToBackend one of embedder messages.

chrome/browser/devtools/devtools_embedder_message_dispatcher.cc

 // Copyright 2013 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 "chrome/browser/devtools/devtools_embedder_message_dispatcher.h"
 
 #include "base/bind.h"
 #include "base/values.h"
 
 namespace {
@@ skipping 271 matching lines @@
                      &Delegate::SetWhitelistedShortcuts, delegate);
   d->RegisterHandler("zoomIn", &Delegate::ZoomIn, delegate);
   d->RegisterHandler("zoomOut", &Delegate::ZoomOut, delegate);
   d->RegisterHandler("resetZoom", &Delegate::ResetZoom, delegate);
   d->RegisterHandler("openUrlOnRemoteDeviceAndInspect",
                      &Delegate::OpenUrlOnRemoteDeviceAndInspect, delegate);
   d->RegisterHandler("setDeviceCountUpdatesEnabled",
                      &Delegate::SetDeviceCountUpdatesEnabled, delegate);
   d->RegisterHandler("setDevicesUpdatesEnabled",
                      &Delegate::SetDevicesUpdatesEnabled, delegate);
+  d->RegisterHandler("sendMessageToBrowser",
+                     &Delegate::SendMessageToBrowser, delegate);
   return d;
 }