Remove unused parts of //mojo/common.

mojo/common/user_agent.cc

Index: mojo/common/user_agent.cc
diff --git a/mojo/common/user_agent.cc b/mojo/common/user_agent.cc
deleted file mode 100644
index 6055cbe5aae8c252951f1e8510bb9e9fe9780823..0000000000000000000000000000000000000000
--- a/mojo/common/user_agent.cc
+++ /dev/null
@@ -1,25 +0,0 @@
-// 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 "mojo/common/user_agent.h"
-
-#include "build/build_config.h"
-
-namespace mojo {
-namespace common {
-
-std::string GetUserAgent() {
-  // TODO(jam): change depending on OS
-#if defined(OS_ANDROID)
-  return "Mozilla/5.0 (Linux; Android 5.1.1; Nexus 7 Build/LMY48G) "
-         "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.68 "
-         "Safari/537.36";
-#else
-  return "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like "
-         "Gecko) Chrome/42.0.2311.68 Safari/537.36";
-#endif
-}
-
-}  // namespace common
-}  // namespace mojo