More SQL statement usage regularization. Back-touch some

chrome/browser/history/visit_database.cc

 // 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.
 
 #include "chrome/browser/history/visit_database.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <set>
@@ skipping 88 matching lines @@
   visit->visit_time = base::Time::FromInternalValue(statement.ColumnInt64(2));
   visit->referring_visit = statement.ColumnInt64(3);
   visit->transition = content::PageTransitionFromInt(statement.ColumnInt(4));
   visit->segment_id = statement.ColumnInt64(5);
   visit->is_indexed = !!statement.ColumnInt(6);
 }
 
 // static
 bool VisitDatabase::FillVisitVector(sql::Statement& statement,
                                     VisitVector* visits) {
+  if (!statement.is_valid())
+    return false;
+
   while (statement.Step()) {
     history::VisitRow visit;
     FillVisitRow(statement, &visit);
     visits->push_back(visit);
   }
 
   return statement.Succeeded();
 }
 
 VisitID VisitDatabase::AddVisit(VisitRow* visit, VisitSource source) {
@@ skipping 384 matching lines @@
     // Get the source entries out of the query result.
     while (statement.Step()) {
       std::pair<VisitID, VisitSource> source_entry(statement.ColumnInt64(0),
           static_cast<VisitSource>(statement.ColumnInt(1)));
       sources->insert(source_entry);
     }
   }
 }
 
 }  // namespace history