Use ScopedTaskEnvironment instead of MessageLoop in service_manager::test::ServiceTest.

content/browser/dom_storage/local_storage_context_mojo_unittest.cc

Index: content/browser/dom_storage/local_storage_context_mojo_unittest.cc
diff --git a/content/browser/dom_storage/local_storage_context_mojo_unittest.cc b/content/browser/dom_storage/local_storage_context_mojo_unittest.cc
index f6db98bc6b58d9ae7cf2f55bd4b75cb9f52cb3aa..60b3e98a7d8f6a2e1c1b48a13b23f89cf21672db 100644
--- a/content/browser/dom_storage/local_storage_context_mojo_unittest.cc
+++ b/content/browser/dom_storage/local_storage_context_mojo_unittest.cc
@@ -677,10 +677,6 @@ class LocalStorageContextMojoTestWithService
     return base::MakeUnique<ServiceTestClient>(this);
   }
 
-  std::unique_ptr<base::MessageLoop> CreateMessageLoop() override {
-    return nullptr;

[fdoray, 2017/05/10 16:53:50]

Returning nullptr prevented initialization of a MessageLoop by the base class,
which was required for the TestBrowserThreadBundle member below. This is no
longer required now that TestBrowserThreadBundle can cohabit with
ScopedTaskEnvironment.
https://chromium.googlesource.com/chromium/src/+/8c5805290290f2e7749c27ee7ea0...

-  }
-
   const base::FilePath& temp_path() { return temp_path_.GetPath(); }
 
   base::FilePath FirstEntryInDir() {