[sql] Disable memory-mapping under sql::Recovery.

sql/recovery_unittest.cc

 // Copyright 2013 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 <string>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 674 matching lines @@
     size_t rows = 0;
     EXPECT_TRUE(recovery->AutoRecoverTable("x", 0, &rows));
     EXPECT_EQ(43u, rows);
 
     // Successfully recovered.
     EXPECT_TRUE(sql::Recovery::Recovered(recovery.Pass()));
   }
 }
 #endif  // !defined(USE_SYSTEM_SQLITE)
 
+// Memory-mapped I/O interacts poorly with I/O errors.  Make sure the recovery
+// database doesn't accidentally enable it.
+TEST_F(SQLRecoveryTest, NoMmap) {
+  scoped_ptr<sql::Recovery> recovery = sql::Recovery::Begin(&db(), db_path());
+  ASSERT_TRUE(recovery.get());
+
+  // In the current implementation, the PRAGMA successfully runs with no result
+  // rows.  Running with a single result of |0| is also acceptable.
+  sql::Statement s(recovery->db()->GetUniqueStatement("PRAGMA mmap_size"));
+  EXPECT_TRUE(!s.Step() || !s.ColumnInt64(0));
+}
+
 }  // namespace