Implements TestMessageLoop that flushes pending tasks on destruction.

base/test/test_message_loop.cc

Index: base/test/test_message_loop.cc
diff --git a/base/test/test_message_loop.cc b/base/test/test_message_loop.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cc6a00073d837287d42604eb5038739accb768a5
--- /dev/null
+++ b/base/test/test_message_loop.cc
@@ -0,0 +1,17 @@
+// Copyright 2016 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 "base/test/test_message_loop.h"
+
+namespace base {
+
+TestMessageLoop::TestMessageLoop() {}
+
+TestMessageLoop::TestMessageLoop(MessageLoop::Type type) : loop_(type) {}
+
+TestMessageLoop::~TestMessageLoop() {
+  loop_.RunUntilIdle();
+}
+
+}  // namespace base