[mojo] Replace MessageLoopProxy usage with ThreadTaskRunnerHandle

mojo/runner/in_process_native_runner.cc

Index: mojo/runner/in_process_native_runner.cc
diff --git a/mojo/runner/in_process_native_runner.cc b/mojo/runner/in_process_native_runner.cc
index c37e31ddd2029a841baf877496360889dfa5af55..27b6c3dc085dba4ed9bdc5ffa6b71ead901c13a6 100644
--- a/mojo/runner/in_process_native_runner.cc
+++ b/mojo/runner/in_process_native_runner.cc
@@ -7,7 +7,7 @@
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
-#include "base/message_loop/message_loop_proxy.h"
+#include "base/thread_task_runner_handle.h"
 #include "base/threading/platform_thread.h"
 #include "mojo/runner/native_application_support.h"
 
@@ -43,8 +43,10 @@ void InProcessNativeRunner::Start(
 
   DCHECK(app_completed_callback_runner_.is_null());
   app_completed_callback_runner_ =
-      base::Bind(&base::TaskRunner::PostTask, base::MessageLoopProxy::current(),
-                 FROM_HERE, app_completed_callback);
+      base::Bind(&base::TaskRunner::PostTask,
+                 base::ThreadTaskRunnerHandle::Get(),
+                 FROM_HERE,
+                 app_completed_callback);
 
   DCHECK(!thread_);
   thread_.reset(new base::DelegateSimpleThread(this, "app_thread"));