Move part of metrics from chrome/common to components

components/metrics/proto/chrome_user_metrics_extension.proto

 // Copyright (c) 2012 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.
 //
 // Protocol buffer for Chrome UMA (User Metrics Analysis).
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
@@ skipping 38 matching lines @@
   optional SystemProfileProto system_profile = 3;
 
   // This message will log one or more of the following event types:
   repeated UserActionEventProto user_action_event = 4;
   repeated OmniboxEventProto omnibox_event = 5;
   repeated HistogramEventProto histogram_event = 6;
   repeated ProfilerEventProto profiler_event = 7;
 
   repeated PerfDataProto perf_data = 8;
 }