Extract touchscreen device management into a generic manager

ui/aura/test/aura_test_base.h

Index: ui/aura/test/aura_test_base.h
diff --git a/ui/aura/test/aura_test_base.h b/ui/aura/test/aura_test_base.h
index b9f6e7f68ce309907e9f0571264e7fe43834817d..5927ec07c806e27e18d06116a0ebde5d06ef5f2f 100644
--- a/ui/aura/test/aura_test_base.h
+++ b/ui/aura/test/aura_test_base.h
@@ -5,6 +5,7 @@
 #ifndef UI_AURA_TEST_AURA_TEST_BASE_H_
 #define UI_AURA_TEST_AURA_TEST_BASE_H_
 
+#include "base/at_exit.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop/message_loop.h"
@@ -46,6 +47,7 @@ class AuraTestBase : public testing::Test {
   TestScreen* test_screen() { return helper_->test_screen(); }
 
  private:
+  base::ShadowingAtExitManager at_exit_;
   bool setup_called_;
   bool teardown_called_;
   base::MessageLoopForUI message_loop_;