Modify sync unit test to use standard sql::test:: helper.

sql/test/test_helpers.h

 // 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.
 
 #ifndef SQL_TEST_TEST_HELPERS_H_
 #define SQL_TEST_TEST_HELPERS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 15 matching lines @@
 namespace sql {
 namespace test {
 
 // SQLite stores the database size in the header, and if the actual
 // OS-derived size is smaller, the database is considered corrupt.
 // [This case is actually a common form of corruption in the wild.]
 // This helper sets the in-header size to one page larger than the
 // actual file size.  The resulting file will return SQLITE_CORRUPT
 // for most operations unless PRAGMA writable_schema is turned ON.
 //
+// This function operates on the raw database file, outstanding database
+// connections may not see the change because of the database cache.  See
+// CorruptSizeInHeaderWithLock().
+//
 // Returns false if any error occurs accessing the file.
 bool CorruptSizeInHeader(const base::FilePath& db_path) WARN_UNUSED_RESULT;
 
 // Common implementation of CorruptSizeInHeader() which operates on loaded
 // memory. Shared between CorruptSizeInHeader() and the the mojo proxy testing
 // code.
 void CorruptSizeInHeaderMemory(unsigned char* header, int64_t db_size);
 
+// Call CorruptSizeInHeader() while holding a SQLite-compatible lock
+// on the database.  This can be used to corrupt a database which is
+// already open elsewhere.  Blocks until a write lock can be acquired.
+bool CorruptSizeInHeaderWithLock(
+    const base::FilePath& db_path) WARN_UNUSED_RESULT;
+
 // Frequently corruption is a result of failure to atomically update
 // pages in different structures.  For instance, if an index update
 // takes effect but the corresponding table update does not.  This
 // helper restores the prior version of a b-tree root after running an
 // update which changed that b-tree.  The named b-tree must exist and
 // must be a leaf node (either index or table).  Returns true if the
 // on-disk file is successfully modified, and the restored page
 // differs from the updated page.
 //
 // The resulting database should be possible to open, and many
@@ skipping 31 matching lines @@
 
 // Return the results of running "PRAGMA integrity_check" on |db|.
 // TODO(shess): sql::Connection::IntegrityCheck() is basically the
 // same, but not as convenient for testing.  Maybe combine.
 std::string IntegrityCheck(sql::Connection* db) WARN_UNUSED_RESULT;
 
 }  // namespace test
 }  // namespace sql
 
 #endif  // SQL_TEST_TEST_HELPERS_H_