Revert of Straightens outs DEPS in mojo/common

components/message_port/BUILD.gn

 # 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.
 
 source_set("message_port") {
   sources = [
     "web_message_port_channel_impl.cc",
     "web_message_port_channel_impl.h",
   ]
 
   public_deps = [
     "//base",
-    "//mojo/message_pump",
+    "//mojo/common",
     "//third_party/WebKit/public:blink",
     "//third_party/mojo/src/mojo/public/cpp/system",
   ]
 }