Collect UMA statistics on which chrome://flags lead to chrome restart on ChromeOS.

tools/about_flags_switches_histogram_ids_checker/changed_file_3.h

 // 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.
 
 #ifndef MOCK_ENUM_H
 #define MOCK_ENUM_H
 
 // Here is our mock enum. Beyond testing it is completely meaningless.
 // MockEnum follows strict rules for valid modifications:
 //    1. NO reordering of entries
 //    2. NO deletions of entries
 //    3. New entries must be added just before mBoundary, never after
 //
 enum MockEnum {
-  mEntry1,
-  mEntry2,
-  mData1,
-  mData2,
-  mEntry3,
-  mInfo1,
-  mData3,
-  mErrata1,
-  mFunction1,
-  mInfo2,
-  mData4,
-  mBoundary // Do not add below here
+  UMA_HISTOGRAM_ID_Entry1,
+  UMA_HISTOGRAM_ID_Entry2,
+  UMA_HISTOGRAM_ID_Data1,
+  UMA_HISTOGRAM_ID_Data2,
+  UMA_HISTOGRAM_ID_Entry3,
+  UMA_HISTOGRAM_ID_Info1,
+  UMA_HISTOGRAM_ID_Data3,
+  UMA_HISTOGRAM_ID_Errata1,
+  UMA_HISTOGRAM_ID_Function1,
+  UMA_HISTOGRAM_ID_Info2,
+  UMA_HISTOGRAM_ID_Data4,
 };
 
 #endif