Remove calls to deprecated MessageLoop methods in extensions.

extensions/browser/api/storage/storage_frontend_unittest.cc

Index: extensions/browser/api/storage/storage_frontend_unittest.cc
diff --git a/extensions/browser/api/storage/storage_frontend_unittest.cc b/extensions/browser/api/storage/storage_frontend_unittest.cc
index 5517b64d1a547deaaa953ebd1f8406e849b5133a..64339dbf4275c76ccf4f0f7a078c0bb74ca19fb0 100644
--- a/extensions/browser/api/storage/storage_frontend_unittest.cc
+++ b/extensions/browser/api/storage/storage_frontend_unittest.cc
@@ -56,7 +56,7 @@ class ExtensionSettingsFrontendTest : public ExtensionsTest {
   void TearDown() override {
     frontend_.reset();
     // Execute any pending deletion tasks.
-    message_loop_.RunUntilIdle();
+    base::RunLoop().RunUntilIdle();
     ExtensionsTest::TearDown();
   }