Replace MessageLoopProxy with ThreadTaskRunnerHandle in src/sync/.

sync/syncable/syncable_unittest.cc

 // Copyright 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 <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
@@ skipping 106 matching lines @@
 TestDirectory::TestDirectory(Encryptor* encryptor,
                              UnrecoverableErrorHandler* handler,
                              TestBackingStore* backing_store)
     : Directory(backing_store, handler, NULL, NULL, NULL),
       backing_store_(backing_store) {
 }
 
 TestDirectory::~TestDirectory() { }
 
 TEST(OnDiskSyncableDirectory, FailInitialWrite) {
+  base::MessageLoop message_loop;

[maniscalco, 2014/07/09 18:53:40]

You may be wondering why the heck are we adding a MessageLoop here?

The root cause is a small difference in behavior between 
MessageLoopProxy::current() and ThreadTaskRunnerHandle::Get().  Deep down this
test case invokes WeakCore's ctor which calls TTRH::Get.  MLP::current will
happily return null when there is no ML, however, TTRH::Get will DCHECK.

   FakeEncryptor encryptor;
   TestUnrecoverableErrorHandler handler;
   base::ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   base::FilePath file_path = temp_dir.path().Append(
       FILE_PATH_LITERAL("Test.sqlite3"));
   std::string name = "user@x.com";
   NullDirectoryChangeDelegate delegate;
 
   scoped_ptr<TestDirectory> test_dir(
@@ skipping 536 matching lines @@
 TEST_F(SyncableClientTagTest, TestClientTagIndexDuplicateServer) {
   EXPECT_TRUE(CreateWithDefaultTag(factory_.NewServerId(), true));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewServerId(), true));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewServerId(), false));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewLocalId(), false));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewLocalId(), true));
 }
 
 }  // namespace syncable
 }  // namespace syncer