WIP: Eliminate event.target() usage from TrayEventFilter

components/mus/public/cpp/lib/window_tree_client_impl.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 "components/mus/public/cpp/lib/window_tree_client_impl.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 893 matching lines @@
     return;
 
   WindowPrivate(window).LocalSetSharedProperty(name, std::move(new_data));
 }
 
 void WindowTreeClientImpl::OnWindowInputEvent(uint32_t event_id,
                                               Id window_id,
                                               mojom::EventPtr event,
                                               uint32_t event_observer_id) {
   std::unique_ptr<ui::Event> ui_event = event.To<std::unique_ptr<ui::Event>>();
+  Window* window = GetWindowByServerId(window_id);  // May be null.
 
   // Non-zero event_observer_id means it matched an event observer on the
   // server.
   if (event_observer_id != 0 && has_event_observer_ &&
       event_observer_id == event_observer_id_)
-    delegate_->OnEventObserved(*ui_event);
+    delegate_->OnEventObserved(*ui_event, window);
 
-  Window* window = GetWindowByServerId(window_id);
   if (!window || !window->input_event_handler_) {
     tree_->OnWindowInputEventAck(event_id, mojom::EventResult::UNHANDLED);
     return;
   }
 
   std::unique_ptr<base::Callback<void(mojom::EventResult)>> ack_callback(
       new base::Callback<void(mojom::EventResult)>(
           base::Bind(&mojom::WindowTree::OnWindowInputEventAck,
                      base::Unretained(tree_), event_id)));
   window->input_event_handler_->OnWindowInputEvent(
       window, *event.To<std::unique_ptr<ui::Event>>().get(), &ack_callback);
 
   // The handler did not take ownership of the callback, so we send the ack,
   // marking the event as not consumed.
   if (ack_callback)
     ack_callback->Run(mojom::EventResult::UNHANDLED);
 }
 
 void WindowTreeClientImpl::OnEventObserved(mojom::EventPtr event,
                                            uint32_t event_observer_id) {
   if (has_event_observer_ && event_observer_id == event_observer_id_) {
     std::unique_ptr<ui::Event> ui_event =
         event.To<std::unique_ptr<ui::Event>>();
-    delegate_->OnEventObserved(*ui_event);
+    delegate_->OnEventObserved(*ui_event, nullptr /* target */);
   }
 }
 
 void WindowTreeClientImpl::OnWindowFocused(Id focused_window_id) {
   Window* focused_window = GetWindowByServerId(focused_window_id);
   InFlightFocusChange new_change(this, focused_window);
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
   LocalSetFocus(focused_window);
@@ skipping 137 matching lines @@
 
 void WindowTreeClientImpl::SetUnderlaySurfaceOffsetAndExtendedHitArea(
     Window* window,
     const gfx::Vector2d& offset,
     const gfx::Insets& hit_area) {
   window_manager_internal_client_->SetUnderlaySurfaceOffsetAndExtendedHitArea(
       server_id(window), offset.x(), offset.y(), mojo::Insets::From(hit_area));
 }
 
 }  // namespace mus