Add UMA reporting of reset request origin.

chrome/browser/profile_resetter/profile_reset_report.proto

 // 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.
 //
 // Sync protocol for sending reset reports.
 
 syntax = "proto2";
 
 package reset_report;
 
@@ skipping 44 matching lines @@
   message Extension {
     optional string extension_id = 1;
     optional string extension_name = 2;
   }
 
   repeated Extension enabled_extensions = 17;
 
   // Full command line (executable and parameters) of shotcuts to start Chrome.
   repeated string shortcuts = 18;
 
-  // Specifies where the request for the settings reset came from.
+  // Specifies where the request for the settings reset came from. If
+  // you add new enumerators, also update
+  // "ProfileResetRequestOriginEnum" in tools/metrics/histograms/histograms.xml.
   enum ResetRequestOrigin {
     RESET_REQUEST_ORIGIN_UNSPECIFIED = 0;
     // None of the other cases. Possibly by navigating to
     // chrome://settings/resetProfileSettings directly or launching
     // chrome with that URL as an argument.
     RESET_REQUEST_ORIGIN_UNKNOWN = 1;
     // User clicked on the reset button on the settings page.
     RESET_REQUEST_ORIGIN_USER_CLICK = 2;
     // A settings reset was requested by the Chrome Cleanup Tool.
     RESET_REQUEST_ORIGIN_CCT = 3;
     // The triggered settings reset API was used.
     RESET_REQUEST_ORIGIN_TRIGGERED_RESET = 4;
   }
 
   optional ResetRequestOrigin reset_request_origin = 19;
 
   // next available tag number: 20.
 }