Initialize shell and browser thread for views event tests.

chrome/test/base/view_event_test_base.h

Index: chrome/test/base/view_event_test_base.h
diff --git a/chrome/test/base/view_event_test_base.h b/chrome/test/base/view_event_test_base.h
index 556f65aaf9220cfef80e75aaab5a7094ebb4e143..b4eda6039e9dfe15529a18a1dd2617ea1e7baaee 100644
--- a/chrome/test/base/view_event_test_base.h
+++ b/chrome/test/base/view_event_test_base.h
@@ -16,6 +16,7 @@
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 #include "base/threading/thread.h"
+#include "content/test/test_browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/views/widget/widget_delegate.h"
 
@@ -134,6 +135,8 @@ class ViewEventTestBase : public views::WidgetDelegate,
 
   MessageLoopForUI message_loop_;
 
+  content::TestBrowserThread ui_thread_;
+
   // Method factory used for time-outs.
   ScopedRunnableMethodFactory<ViewEventTestBase> method_factory_;