Remove use of deprecated MessageLoop methods in cc.

cc/trees/layer_tree_host_unittest_copyrequest.cc

Index: cc/trees/layer_tree_host_unittest_copyrequest.cc
diff --git a/cc/trees/layer_tree_host_unittest_copyrequest.cc b/cc/trees/layer_tree_host_unittest_copyrequest.cc
index b92c687529b3f31449e347ab7428e9f2c823ac00..6b2f57f95277cfe29c235554e93598b86a0a5199 100644
--- a/cc/trees/layer_tree_host_unittest_copyrequest.cc
+++ b/cc/trees/layer_tree_host_unittest_copyrequest.cc
@@ -4,7 +4,10 @@
 
 #include <stddef.h>
 
+#include "base/location.h"
 #include "base/memory/ptr_util.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "cc/layers/layer_iterator.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/output/copy_output_result.h"
@@ -47,7 +50,7 @@ class LayerTreeHostCopyRequestTestMultipleRequests
   void DidCommit() override { WaitForCallback(); }
 
   void WaitForCallback() {
-    base::MessageLoop::current()->PostTask(
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::Bind(&LayerTreeHostCopyRequestTestMultipleRequests::NextStep,
                    base::Unretained(this)));