Stop Using MessageLoopProxy in Test Since It's Deprecated

Fix a recent use of MessageLoopProxy in test.

BUG=

Review URL: https://codereview.chromium.org/1063823007

Cr-Commit-Position: refs/heads/master@{#326365}

ui/compositor/compositor_unittest.cc

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/message_loop/message_loop_proxy.h"
 #include "base/run_loop.h"
+#include "base/thread_task_runner_handle.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/test/begin_frame_args_test.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -30,7 +30,7 @@ class CompositorTest : public testing::Test {
   ~CompositorTest() override {}
 
   void SetUp() override {
-    task_runner_ = base::MessageLoopProxy::current();
+    task_runner_ = base::ThreadTaskRunnerHandle::Get();
 
     ui::ContextFactory* context_factory =
         ui::InitializeContextFactoryForTests(false);
@@ -44,11 +44,11 @@ class CompositorTest : public testing::Test {
   }
 
  protected:
-  base::MessageLoopProxy* task_runner() { return task_runner_.get(); }
+  base::SingleThreadTaskRunner* task_runner() { return task_runner_.get(); }
   ui::Compositor* compositor() { return compositor_.get(); }
 
  private:
-  scoped_refptr<base::MessageLoopProxy> task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_ptr<ui::Compositor> compositor_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorTest);