Move part of metrics from chrome/common to components

components/metrics/proto/system_profile.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.
 //
 // Stores information about the user's brower and system configuration.
 // The system configuration fields are recorded once per client session.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
@@ skipping 489 matching lines @@
   // client_id:
   //   client_key = client_id % 4096
   // Then, each installed extension is mapped into a hash bucket according to
   //   bucket = CityHash64(StringPrintf("%d:%s",
   //                                    client_key, extension_id)) % 1024
   // The client reports the set of hash buckets occupied by all installed
   // extensions.  If multiple extensions map to the same bucket, that bucket is
   // still only reported once.
   repeated int32 occupied_extension_bucket = 18;
 }