Remove calls to deprecated MessageLoop methods in chrome.

This CL makes the following replacements in
chrome:

Before               After
----------------------------------------------------------
 x.PostTask()          x.task_runner()->PostTask()
   PostDelayedTask()                    PostDelayedTask()
   ReleaseSoon()                        ReleaseSoon()
   DeleteSoon()                         DeleteSoon()
x->PostTask()         y->task_runner()->PostTask()
   PostDelayedTask()                    PostDelayedTask()
   ReleaseSoon()                        ReleaseSoon()
   DeleteSoon()                         DeleteSoon()

 x.Run()              RunLoop().Run()
 x.RunUntilIdle()     RunLoop().RunUntilIdle()

x->Run()              RunLoop().Run()
x->RunUntilIdle()     RunLoop().RunUntilIdle()
    If |y| isn't MessageLoopForUI::current() or
    MessageLoopForIO::current()

 y.message_loop()->task_runner()
                      y.task_runner()
y->message_loop()->task_runner()
                      y->task_runner()
----------------------------------------------------------

|x| is a base::MessageLoop(ForUI|ForIO) or a pointer to
a base::MessageLoop(ForUI|ForIO). |y| is a base::Thread
or a pointer to a base::Thread.

This CL was generated using the MessageLoopDeprecatedMethods
clang-tidy fix available on the associated bug. Only files
that compile on Mac are affected. Follow-up CLs will make
these replacements for other platforms.

This CL doesn't change code behavior.

BUG=616447
[email protected]

Review-Url: https://codereview.chromium.org/2083363002
Cr-Commit-Position: refs/heads/master@{#401614}
diff --git a/chrome/browser/extensions/extension_web_ui_unittest.cc b/chrome/browser/extensions/extension_web_ui_unittest.cc
index f96b526..0a85885a5 100644
--- a/chrome/browser/extensions/extension_web_ui_unittest.cc
+++ b/chrome/browser/extensions/extension_web_ui_unittest.cc
@@ -7,6 +7,7 @@
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_web_ui_override_registrar.h"
@@ -55,7 +56,7 @@
 
   void TearDown() override {
     profile_.reset();
-    message_loop_.RunUntilIdle();
+    base::RunLoop().RunUntilIdle();
   }
 
   std::unique_ptr<TestingProfile> profile_;