Change OnWindowInputEvent to use display_id to find the host and update event root_location in WS.

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 bc00034df1b57ced12c7b4e8cd97573612256d7d..9ab79f3ab78456d2872111b15393651d3b928e91 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -160,10 +160,21 @@ void ConvertEventLocationToDip(int64_t display_id, ui::LocatedEvent* event) {
 
 // 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);
+void DispatchEventToTarget(ui::Event* event,
+                           WindowTreeHostMus* host,
+                           WindowMus* target) {
+  // Set the event target if target window is not null, otherwise update event
+  // location to use its root location and leave the event target empty so we
+  // can find the next best target window starting from root window to dispatch
+  // the event to in EventProcessor.

[sadrul, 2017/03/15 01:21:17]

Merge this with the comment in 161:162

[riajiang, 2017/03/15 15:35:57]

Done.

+  if (target) {
+    ui::Event::DispatcherApi dispatch_helper(event);
+    dispatch_helper.set_target(target->GetWindow());
+  } else if (event->IsLocatedEvent()) {
+    event->AsLocatedEvent()->set_location(

[sadrul, 2017/03/15 01:21:17]

Actually, move the comment about changing the event-location here. Maybe
something like:

"""The target window specified by the window server no longer exists. So it is
necessary to find the target using the local event targeters. For that to work
correctly, the event-location needs to be in the root window's coordinate
space."""

[riajiang, 2017/03/15 15:35:57]

Done.

+        event->AsLocatedEvent()->root_location());
+  }
+  host->SendEventToProcessor(event);
 }
 
 }  // namespace
@@ -1128,19 +1139,9 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
                                           bool matches_pointer_watcher) {
   DCHECK(event);
 
-  WindowMus* window = GetWindowByServerId(window_id);  // May be null.
-
-  if (event->IsKeyEvent()) {
-    DCHECK(!matches_pointer_watcher);  // PointerWatcher isn't for key events.
-    if (!window || !window->GetWindow()->GetHost()) {
-      tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
-      return;
-    }
-    InputMethodMus* input_method = GetWindowTreeHostMus(window)->input_method();
-    input_method->DispatchKeyEvent(event->AsKeyEvent(),
-                                   CreateEventResultCallback(event_id));
-    return;
-  }
+  // |window| may be null if it has already been deleted as OnWindowInputEvent
+  // is being called asynchronously.
+  WindowMus* window = GetWindowByServerId(window_id);
 
   if (matches_pointer_watcher && has_pointer_watcher_) {
     DCHECK(event->IsPointerEvent());
@@ -1150,28 +1151,39 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
                                       window ? window->GetWindow() : nullptr);
   }
 
-  // TODO: use |display_id| to find host and send there.
-  if (!window || !window->GetWindow()->GetHost()) {
+  // Since this |window| might have already been deleted by the time
+  // OnWindowInputEvent is called, so we use the |display_id| to find the host

[sadrul, 2017/03/15 01:21:17]

s/so//

[riajiang, 2017/03/15 15:35:57]

Done.

+  // for event dispatching.
+  WindowTreeHostMus* host = GetWindowTreeHostMusWithDisplayId(display_id);

[sadrul, 2017/03/15 01:21:17]

Should this be:

  host = window ? window->GetHost() :
GetWindowTreeHostMusWithDisplayId(display_id);

[riajiang, 2017/03/15 15:35:57]

Done.

+  if (!host) {
     tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
     return;
   }
 
+  if (event->IsKeyEvent()) {
+    DCHECK(!matches_pointer_watcher);  // PointerWatcher isn't for key events.
+    InputMethodMus* input_method = host->input_method();
+    input_method->DispatchKeyEvent(event->AsKeyEvent(),
+                                   CreateEventResultCallback(event_id));
+    return;
+  }
+
   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());
-      DispatchEventToTarget(&mapped_event, window);
+      DispatchEventToTarget(&mapped_event, host, window);
     } else {
       ui::MouseEvent mapped_event(*event->AsPointerEvent());
-      DispatchEventToTarget(&mapped_event, window);
+      DispatchEventToTarget(&mapped_event, host, window);
     }
   } else if (event->IsTouchPointerEvent()) {
     ui::TouchEvent mapped_event(*event->AsPointerEvent());
-    DispatchEventToTarget(&mapped_event, window);
+    DispatchEventToTarget(&mapped_event, host, window);
   } else {
-    DispatchEventToTarget(event.get(), window);
+    DispatchEventToTarget(event.get(), host, window);
   }
   ack_handler.set_handled(event->handled());
 }
@@ -1328,15 +1340,9 @@ void WindowTreeClient::WmNewDisplayAdded(const display::Display& display,
 
 void WindowTreeClient::WmDisplayRemoved(int64_t display_id) {
   DCHECK(window_manager_delegate_);
-  for (WindowMus* root : roots_) {
-    DCHECK(root->GetWindow()->GetHost());
-    WindowTreeHostMus* window_tree_host =
-        static_cast<WindowTreeHostMus*>(root->GetWindow()->GetHost());
-    if (window_tree_host->display_id() == display_id) {
-      window_manager_delegate_->OnWmDisplayRemoved(window_tree_host);
-      return;
-    }
-  }
+  WindowTreeHostMus* host = GetWindowTreeHostMusWithDisplayId(display_id);
+  if (host)
+    window_manager_delegate_->OnWmDisplayRemoved(host);
 }
 
 void WindowTreeClient::WmDisplayModified(const display::Display& display) {
@@ -1827,4 +1833,18 @@ uint32_t WindowTreeClient::CreateChangeIdForFocus(WindowMus* window) {
       this, focus_synchronizer_.get(), window));
 }
 
+WindowTreeHostMus* WindowTreeClient::GetWindowTreeHostMusWithDisplayId(
+    int64_t display_id) {
+  // TODO(riajiang): Figure out how to get the correct WindowTreeHost we need
+  // in external window mode.
+  for (WindowMus* root : roots_) {
+    DCHECK(root->GetWindow()->GetHost());
+    WindowTreeHostMus* window_tree_host =
+        static_cast<WindowTreeHostMus*>(root->GetWindow()->GetHost());
+    if (window_tree_host->display_id() == display_id)
+      return window_tree_host;
+  }
+  return nullptr;
+}
+
 }  // namespace aura