Removing deprecated ios/web/user_metrics.cc and references to it.

ios/web/user_metrics.cc

-// Copyright 2014 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 "ios/web/public/user_metrics.h"
-
-#include <vector>
-
-#include "base/bind.h"
-#include "base/location.h"
-#include "base/metrics/user_metrics.h"
-#include "ios/web/public/web_thread.h"
-
-namespace web {
-
-// TODO(beaudoin): Get rid of these methods now that the base:: version does
-// thread hopping. Tracked in crbug.com/601483.
-void RecordAction(const base::UserMetricsAction& action) {
-  base::RecordAction(action);
-}
-
-void RecordComputedAction(const std::string& action) {
-  base::RecordComputedAction(action);
-}
-
-}  // namespace web