Fix sticky keys crash when handling synthetic events without a native event.

ash/sticky_keys/sticky_keys_controller.cc

Index: ash/sticky_keys/sticky_keys_controller.cc
diff --git a/ash/sticky_keys/sticky_keys_controller.cc b/ash/sticky_keys/sticky_keys_controller.cc
index e5bb0afe2483c32c1dbd4a20dfff9f6583cf4c8b..f313e7303656f5e5cb5151515ca31e464ba32a76 100644
--- a/ash/sticky_keys/sticky_keys_controller.cc
+++ b/ash/sticky_keys/sticky_keys_controller.cc
@@ -69,11 +69,31 @@ void StickyKeysHandlerDelegateImpl::DispatchMouseEvent(ui::MouseEvent* event,
   DCHECK(target);
   // We need to send a new, untransformed mouse event to the host.
   if (event->IsMouseWheelEvent()) {
-    ui::MouseWheelEvent new_event(event->native_event());
-    DispatchEvent(&new_event, target);
+    if (event->HasNativeEvent()) {
+      ui::MouseWheelEvent new_event(event->native_event());
+      DispatchEvent(&new_event, target);
+    } else {
+      aura::Window* source = static_cast<aura::Window*>(event->target());
+      ui::MouseWheelEvent new_event(*static_cast<ui::MouseWheelEvent*>(event),
+                                    source,
+                                    source->GetRootWindow(),
+                                    event->type(),
+                                    event->flags());

[sadrul, 2014/04/07 21:57:33]

It looks like this ctor for MouseWheelEvent is not used anywhere. Mind changing
the ctor so it doesn't take the EventType or the flags as parameters?

[Tim Song, 2014/04/07 22:23:27]

Done.

+      // Transform the location back to host coordinates before dispatching.
+      new_event.UpdateForRootTransform(source->GetHost()->GetRootTransform());
+      DispatchEvent(&new_event, target);
+    }
   } else {
-    ui::MouseEvent new_event(event->native_event());
-    DispatchEvent(&new_event, target);
+    if (event->HasNativeEvent()) {
+      ui::MouseEvent new_event(event->native_event());
+      DispatchEvent(&new_event, target);
+    } else {
+      aura::Window* source = static_cast<aura::Window*>(event->target());
+      ui::MouseEvent new_event(*event, source, source->GetRootWindow());
+      // Transform the location back to host coordinates before dispatching.
+      new_event.UpdateForRootTransform(source->GetHost()->GetRootTransform());
+      DispatchEvent(&new_event, target);
+    }

[sadrul, 2014/04/07 21:57:33]

You can always just create the new event out of the modified event and dispatch
that, right? Does creating the event from the X event give you any benefit?

[Tim Song, 2014/04/07 22:23:27]

Done. You're right, it should be equivalent in this case.

   }
 }