Use base::MessageLoop in more files.

android_webview/browser/aw_form_database_service_unittest.cc

Index: android_webview/browser/aw_form_database_service_unittest.cc
diff --git a/android_webview/browser/aw_form_database_service_unittest.cc b/android_webview/browser/aw_form_database_service_unittest.cc
index e269a625f57a796bde6d86431edc93b50d8584b2..6f8e41006c04f9294230c4a83106626906816fbc 100644
--- a/android_webview/browser/aw_form_database_service_unittest.cc
+++ b/android_webview/browser/aw_form_database_service_unittest.cc
@@ -49,7 +49,7 @@ class AwFormDatabaseServiceTest : public Test {
   // The path to the temporary directory used for the test operations.
   base::ScopedTempDir temp_dir_;
   // A message loop for UI thread.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   JNIEnv* env_;