Let IPC::SyncMessageFilter take advantage of thread-safe Send.

content/child/indexed_db/indexed_db_dispatcher_unittest.cc

Index: content/child/indexed_db/indexed_db_dispatcher_unittest.cc
diff --git a/content/child/indexed_db/indexed_db_dispatcher_unittest.cc b/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
index 7e146e7b00b46bf37464f241f493bd99346f3510..6e72d7bf30b634c74d5929aad8fd69b8966b4433 100644
--- a/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
+++ b/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
@@ -60,22 +60,27 @@ class MockDispatcher : public IndexedDBDispatcher {
   DISALLOW_COPY_AND_ASSIGN(MockDispatcher);
 };
 
+class MockSyncMessageFilter : public IPC::SyncMessageFilter {
+ public:
+  MockSyncMessageFilter()
+      : SyncMessageFilter(nullptr, false /* is_channel_send_thread_safe */) {}
+
+ private:
+  ~MockSyncMessageFilter() override {}
+};
+
 }  // namespace
 
 class IndexedDBDispatcherTest : public testing::Test {
  public:
   IndexedDBDispatcherTest()
-      : task_runner_(base::ThreadTaskRunnerHandle::Get()),
-        sync_message_filter_(new IPC::SyncMessageFilter(NULL)),
-        thread_safe_sender_(new ThreadSafeSender(task_runner_.get(),
-                                                 sync_message_filter_.get())) {}
+      : thread_safe_sender_(new ThreadSafeSender(
+            base::ThreadTaskRunnerHandle::Get(), new MockSyncMessageFilter)) {}
 
   void TearDown() override { blink::WebHeap::collectAllGarbageForTesting(); }
 
  protected:
   base::MessageLoop message_loop_;
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-  scoped_refptr<IPC::SyncMessageFilter> sync_message_filter_;
   scoped_refptr<ThreadSafeSender> thread_safe_sender_;
 
  private: