Revert of base: Remove use of MessageLoopProxy

base/test/launcher/unit_test_launcher.cc

Index: base/test/launcher/unit_test_launcher.cc
diff --git a/base/test/launcher/unit_test_launcher.cc b/base/test/launcher/unit_test_launcher.cc
index ab6fa7220441eab3aebe891150bc934927f098fb..1b3a162c661ac25f419ed477764f5d935b467221 100644
--- a/base/test/launcher/unit_test_launcher.cc
+++ b/base/test/launcher/unit_test_launcher.cc
@@ -12,9 +12,7 @@
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/format_macros.h"
-#include "base/location.h"
 #include "base/message_loop/message_loop.h"
-#include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ -24,7 +22,6 @@
 #include "base/test/test_switches.h"
 #include "base/test/test_timeouts.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
-#include "base/thread_task_runner_handle.h"
 #include "base/threading/thread_checker.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -408,10 +405,13 @@
   // The temporary file's directory is also temporary.
   DeleteFile(callback_state.output_file.DirName(), true);
 
-  ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, Bind(&RunUnitTestsSerially, callback_state.test_launcher,
-                      callback_state.platform_delegate, test_names,
-                      callback_state.launch_flags));
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      Bind(&RunUnitTestsSerially,
+           callback_state.test_launcher,
+           callback_state.platform_delegate,
+           test_names,
+           callback_state.launch_flags));
 }
 
 }  // namespace
@@ -576,9 +576,12 @@
 size_t UnitTestLauncherDelegate::RetryTests(
     TestLauncher* test_launcher,
     const std::vector<std::string>& test_names) {
-  ThreadTaskRunnerHandle::Get()->PostTask(
+  MessageLoop::current()->PostTask(
       FROM_HERE,
-      Bind(&RunUnitTestsSerially, test_launcher, platform_delegate_, test_names,
+      Bind(&RunUnitTestsSerially,
+           test_launcher,
+           platform_delegate_,
+           test_names,
            use_job_objects_ ? TestLauncher::USE_JOB_OBJECTS : 0));
   return test_names.size();
 }