IPC: Delete thread-safe send support

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 029689f388eb7b134735e19390b0546b11017829..0acc1f143da50df7761be82ee236f08732068ee2 100644
--- a/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
+++ b/content/child/indexed_db/indexed_db_dispatcher_unittest.cc
@@ -54,8 +54,7 @@ class MockDispatcher : public IndexedDBDispatcher {
 
 class MockSyncMessageFilter : public IPC::SyncMessageFilter {
  public:
-  MockSyncMessageFilter()
-      : SyncMessageFilter(nullptr, false /* is_channel_send_thread_safe */) {}
+  MockSyncMessageFilter() : SyncMessageFilter(nullptr) {}
 
  private:
   ~MockSyncMessageFilter() override {}