Avoid two targeting phases in aura client-lib and EventProcessor.

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index 0f7351c738917443789d004d657cba9e57e89b8b..934261571eae24565c6abb99a6eb7cb4782885f0 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -160,6 +160,14 @@ void ConvertEventLocationToDip(int64_t display_id, ui::LocatedEvent* event) {
   event->set_root_location(root_location);
 }
 
+// Set the |target| to be the target window of this |event| and send it to
+// the EventProcessor.
+void DispatchEventToTarget(ui::Event* event, WindowMus* target) {
+  ui::Event::DispatcherApi dispatch_helper(event);
+  dispatch_helper.set_target(target->GetWindow());
+  GetWindowTreeHostMus(target)->SendEventToProcessor(event);
+}
+
 }  // namespace
 
 WindowTreeClient::WindowTreeClient(
@@ -1150,34 +1158,22 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
     return;
   }
 
-  WindowTreeHostMus* host = GetWindowTreeHostMus(window);
-  DCHECK(host);
-
-  // The location of the event is relative to |window|. As the event is handed
-  // to WindowTreeHost we need it to be relative to WindowTreeHost.
-  if (event->IsLocatedEvent()) {
-    gfx::Point host_location = event->AsLocatedEvent()->location();
-    aura::Window::ConvertPointToTarget(window->GetWindow(), host->window(),
-                                       &host_location);
-    event->AsLocatedEvent()->set_location(host_location);
-  }
-
   EventAckHandler ack_handler(CreateEventResultCallback(event_id));
   // TODO(moshayedi): crbug.com/617222. No need to convert to ui::MouseEvent or
   // ui::TouchEvent once we have proper support for pointer events.
   if (event->IsMousePointerEvent()) {
     if (event->type() == ui::ET_POINTER_WHEEL_CHANGED) {
       ui::MouseWheelEvent mapped_event(*event->AsPointerEvent());
-      host->SendEventToProcessor(&mapped_event);
+      DispatchEventToTarget(&mapped_event, window);
     } else {
       ui::MouseEvent mapped_event(*event->AsPointerEvent());
-      host->SendEventToProcessor(&mapped_event);
+      DispatchEventToTarget(&mapped_event, window);
     }
   } else if (event->IsTouchPointerEvent()) {
     ui::TouchEvent mapped_event(*event->AsPointerEvent());
-    host->SendEventToProcessor(&mapped_event);
+    DispatchEventToTarget(&mapped_event, window);
   } else {
-    host->SendEventToProcessor(event.get());
+    DispatchEventToTarget(event.get(), window);
   }
   ack_handler.set_handled(event->handled());
 }