Generalize the HIT_TEST accessibility action so that it can send any event.

ui/accessibility/ax_action_data.h

Index: ui/accessibility/ax_action_data.h
diff --git a/ui/accessibility/ax_action_data.h b/ui/accessibility/ax_action_data.h
index 4c0af535749aac9163dd87fc87832cba42cf9dc7..cc6e8562cfb9576cd0a2a2a1d6bb1ebddee533cf 100644
--- a/ui/accessibility/ax_action_data.h
+++ b/ui/accessibility/ax_action_data.h
@@ -53,6 +53,9 @@ struct AX_EXPORT AXActionData {
 
   // The new value for a node, for the SET_VALUE action.
   base::string16 value;
+
+  // The event to fire in response to a HIT_TEST action.
+  AXEvent hit_test_event_to_fire;
 };
 
 }  // namespace ui