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

ui/aura/mus/window_tree_client.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/aura/mus/window_tree_client.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
@@ skipping 29 matching lines @@
 #include "ui/aura/mus/window_tree_client_observer.h"
 #include "ui/aura/mus/window_tree_client_test_observer.h"
 #include "ui/aura/mus/window_tree_host_mus.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/events/event.h"
+#include "ui/events/event_processor.h"
 #include "ui/gfx/geometry/dip_util.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/size.h"
 
 #if defined(HiWord)
 #undef HiWord
 #endif
 #if defined(LoWord)
 #undef LoWord
 #endif
@@ skipping 1082 matching lines @@
   // dispatch a window is deleted or moved. In either case we still need to
   // dispatch. Most likely need the display id.
   if (!window || !window->GetWindow()->GetHost()) {
     tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
     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);
-  }
+  // Send the target window that this event should be dispatched to to the event
+  // processor.
+  window->GetWindow()->GetHost()->event_processor()->set_event_target(
+      window->GetWindow());

[sadrul, 2017/02/07 04:04:54]

This is somewhat awkward.

Can we set ui::Event::target_ from here instead? And update the code in
EventProcessor so that it doesn't use the targeter if the event already has a
target set?

[sky, 2017/02/07 04:19:48]

Extremely!
What's wrong with trying to find the location again?

[riajiang, 2017/02/07 17:42:40]

Done! I didn't know we can set the target for an event directly.
But when we create an event from another event (e.g. a mouse event from pointer
event), we don't want to copy over the target right? So I added the target each
time after we do the event conversion... 

 
   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);
     } else {
       ui::MouseEvent mapped_event(*event->AsPointerEvent());
@@ skipping 648 matching lines @@
   return ScheduleInFlightChange(base::MakeUnique<InFlightCaptureChange>(
       this, capture_synchronizer_.get(), window));
 }
 
 uint32_t WindowTreeClient::CreateChangeIdForFocus(WindowMus* window) {
   return ScheduleInFlightChange(base::MakeUnique<InFlightFocusChange>(
       this, focus_synchronizer_.get(), window));
 }
 
 }  // namespace aura