Remove calls to deprecated MessageLoop methods in content.

content/browser/storage_partition_impl_unittest.cc

Index: content/browser/storage_partition_impl_unittest.cc
diff --git a/content/browser/storage_partition_impl_unittest.cc b/content/browser/storage_partition_impl_unittest.cc
index a50428018c1863bbe88b7153cfd21fcf4d9089b8..f79529fa367c3376929ed5fc4614b513e71ddaaf 100644
--- a/content/browser/storage_partition_impl_unittest.cc
+++ b/content/browser/storage_partition_impl_unittest.cc
@@ -100,7 +100,7 @@ class AwaitCompletionHelper {
     if (!already_quit_) {
       DCHECK(!start_);
       start_ = true;
-      base::MessageLoop::current()->Run();
+      base::RunLoop().Run();
     } else {
       DCHECK(!start_);
       already_quit_ = false;