[sql] WARN_UNUSED_RESULT on Execute().

chrome/browser/history/visitsegment_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 "chrome/browser/history/visitsegment_database.h"
 
 #include <math.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 42 matching lines @@
     }
 
     if (!GetDB().Execute("CREATE INDEX segments_name ON segments(name)")) {
       NOTREACHED();
       return false;
     }
   }
 
   // This was added later, so we need to try to create it even if the table
   // already exists.
-  GetDB().Execute("CREATE INDEX segments_url_id ON segments(url_id)");
+  if (!GetDB().Execute("CREATE INDEX IF NOT EXISTS segments_url_id ON "
+                       "segments(url_id)"))
+    return false;
 
   // Segment usage table.
   if (!GetDB().DoesTableExist("segment_usage")) {
     if (!GetDB().Execute("CREATE TABLE segment_usage ("
         "id INTEGER PRIMARY KEY,"
         "segment_id INTEGER NOT NULL,"
         "time_slot INTEGER NOT NULL,"
         "visit_count INTEGER DEFAULT 0 NOT NULL)")) {
       NOTREACHED();
       return false;
     }
     if (!GetDB().Execute(
         "CREATE INDEX segment_usage_time_slot_segment_id ON "
         "segment_usage(time_slot, segment_id)")) {
       NOTREACHED();
       return false;
     }
   }
 
   // Added in a later version, so we always need to try to creat this index.
-  GetDB().Execute("CREATE INDEX segments_usage_seg_id "
-                  "ON segment_usage(segment_id)");
+  if (!GetDB().Execute("CREATE INDEX IF NOT EXISTS segments_usage_seg_id "
+                       "ON segment_usage(segment_id)"))
+    return false;
 
   // Presentation index table.
   //
   // Important note:
   // Right now, this table is only used to store the presentation index.
   // If you need to add more columns, keep in mind that rows are currently
   // deleted when the presentation index is changed to -1.
   // See SetPagePresentationIndex() in this file
   if (!GetDB().DoesTableExist("presentation")) {
     if (!GetDB().Execute("CREATE TABLE presentation("
@@ skipping 280 matching lines @@
       NOTREACHED();
       r = false;
     }
     delete_usage.Reset();
     delete_seg.Reset();
   }
   return r;
 }
 
 }  // namespace history