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 08e7b028bf1b90a4a7f6d21a9458623df8459d90..d1bbb792e4ac55a3a861e52897c53c8c3df23db9 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -1117,18 +1117,6 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
 
   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;
-  }
-
   if (matches_pointer_watcher && has_pointer_watcher_) {
     DCHECK(event->IsPointerEvent());
     std::unique_ptr<ui::Event> event_in_dip(ui::Event::Clone(*event));
@@ -1137,14 +1125,30 @@ 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()) {
+  // This |window| might have already been deleted by the time
+  // OnWindowInputEvent is called, so we use the |display_id| to find the host
+  // for event dispatching.
+  WindowTreeHostMus* host = GetWindowTreeHostMusWithDisplayId(display_id);
+  if (!host) {
     tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
     return;
   }

[sadrul, 2017/02/23 17:13:00]

This could be:
  if (!window) {
    ... host = ...;
    window = WindowMus::Get(host->window());
  }

 
-  WindowTreeHostMus* host = GetWindowTreeHostMus(window);
-  DCHECK(host);
+  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;
+  }
+
+  if (!window) {
+    window = WindowMus::Get(host->window());
+    if (event->IsLocatedEvent()) {
+      event->AsLocatedEvent()->set_location(
+          event->AsLocatedEvent()->root_location());
+    }

[sadrul, 2017/02/23 17:13:00]

Why do this?

+  }
 
   // The location of the event is relative to |window|. As the event is handed
   // to WindowTreeHost we need it to be relative to WindowTreeHost.
@@ -1328,14 +1332,10 @@ 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);
+    return;
   }
 }
 
@@ -1827,4 +1827,16 @@ uint32_t WindowTreeClient::CreateChangeIdForFocus(WindowMus* window) {
       this, focus_synchronizer_.get(), window));
 }
 
+WindowTreeHostMus* WindowTreeClient::GetWindowTreeHostMusWithDisplayId(
+    int64_t display_id) {
+  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