Add a separate protector UMA state when backup is overwritten by migration.

chrome/browser/webdata/keyword_table.h

 // 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.
 
 #ifndef CHROME_BROWSER_WEBDATA_KEYWORD_TABLE_H_
 #define CHROME_BROWSER_WEBDATA_KEYWORD_TABLE_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 75 matching lines @@
   static const char kDefaultSearchProviderKey[];
   // Meta table key to store backup value for the default search provider id.
   static const char kDefaultSearchIDBackupKey[];
   // Meta table key to store backup value signature for the default search
   // provider.  The default search provider ID and the |keywords_backup| table
   // are signed.
   static const char kBackupSignatureKey[];
   // Comma-separated list of keyword table column names, in order.
   static const char kKeywordColumns[];
 
-  KeywordTable(sql::Connection* db, sql::MetaTable* meta_table)
-      : WebDatabaseTable(db, meta_table) {}
+  KeywordTable(sql::Connection* db, sql::MetaTable* meta_table);
   virtual ~KeywordTable();
   virtual bool Init() OVERRIDE;
   virtual bool IsSyncable() OVERRIDE;
 
   // Adds a new keyword, updating the id field on success.
   // Returns true if successful.
   bool AddKeyword(const TemplateURLData& data);
 
   // Removes the specified keyword.
   // Returns true if successful.
@@ skipping 84 matching lines @@
                           std::string* result);
 
   // Updates default search provider id backup in |meta| table. Returns
   // true on success. The id is returned back via |id| parameter.
   bool UpdateDefaultSearchProviderIDBackup(TemplateURLID* id);
 
   // Migrates table |name| (which should be either "keywords" or
   // "keywords_backup" from version 44 to version 45.
   bool MigrateKeywordsTableForVersion45(const std::string& name);
 
+  // Whether the backup was overwritten during migration.
+  bool backup_overwritten_;
+
   DISALLOW_COPY_AND_ASSIGN(KeywordTable);
 };
 
 #endif  // CHROME_BROWSER_WEBDATA_KEYWORD_TABLE_H_