[sql] WARN_UNUSED_RESULT on Execute().

chrome/browser/history/text_database.cc

 // Copyright (c) 2011 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.
 
 #include <limits>
 #include <set>
 #include <string>
 
 #include "chrome/browser/history/text_database.h"
 
@@ skipping 183 matching lines @@
   // full-text-search, which is not what we want when retrieving this data).
   if (!db_.DoesTableExist("info")) {
     // Note that there is no point in creating an index over time. Since
     // we must always query the entire FTS table (it can not efficiently do
     // subsets), we will always end up doing that first, and joining the info
     // table off of that.
     if (!db_.Execute("CREATE TABLE info(time INTEGER NOT NULL)"))
       return false;
   }
 
-  // Create the index. This will fail when the index already exists, so we just
-  // ignore the error.
-  db_.Execute("CREATE INDEX info_time ON info(time)");
-  return true;
+  // Create the index.
+  return db_.Execute("CREATE INDEX IF NOT EXISTS info_time ON info(time)");
 }
 
 bool TextDatabase::AddPageData(base::Time time,
                                const std::string& url,
                                const std::string& title,
                                const std::string& contents) {
   sql::Transaction committer(&db_);
   if (!committer.Begin())
     return false;
 
@@ skipping 162 matching lines @@
   } else {
     // Since we got the results in order, we know the last item is the last
     // time we considered.
     *first_time_searched = results->back().time;
   }
 
   statement.Reset();
 }
 
 }  // namespace history