Replace MessageLoopProxy with ThreadTaskRunnerHandle in src/sync/.

sync/internal_api/attachments/fake_attachment_store.cc

Index: sync/internal_api/attachments/fake_attachment_store.cc
diff --git a/sync/internal_api/attachments/fake_attachment_store.cc b/sync/internal_api/attachments/fake_attachment_store.cc
index cb3c3f4bf02f0de2580ec97cf129f6ef9d5a4d5e..92d43c2bcb1895da7ff327de34b3ffc0e6c4664d 100644
--- a/sync/internal_api/attachments/fake_attachment_store.cc
+++ b/sync/internal_api/attachments/fake_attachment_store.cc
@@ -7,9 +7,9 @@
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/memory/ref_counted_memory.h"
-#include "base/message_loop/message_loop_proxy.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
+#include "base/thread_task_runner_handle.h"
 #include "sync/api/attachments/attachment.h"
 
 namespace syncer {
@@ -96,7 +96,7 @@ void FakeAttachmentStore::Backend::Drop(const AttachmentIdList& ids,
 
 FakeAttachmentStore::FakeAttachmentStore(
     const scoped_refptr<base::SequencedTaskRunner>& backend_task_runner)
-    : backend_(new Backend(base::MessageLoopProxy::current())),
+    : backend_(new Backend(base::ThreadTaskRunnerHandle::Get())),
       backend_task_runner_(backend_task_runner) {}
 
 FakeAttachmentStore::~FakeAttachmentStore() {}