Update event states in Env when target window has been destroyed.

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 b69109eb2360aab9f44f2615a3cf70c5837c85c5..81958410a500efd11c7eea5cdc86db3248e3768f 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -29,6 +29,7 @@
 #include "ui/aura/client/drag_drop_client.h"
 #include "ui/aura/client/transient_window_client.h"
 #include "ui/aura/env.h"
+#include "ui/aura/env_input_state_controller.h"
 #include "ui/aura/mus/capture_synchronizer.h"
 #include "ui/aura/mus/drag_drop_controller_mus.h"
 #include "ui/aura/mus/focus_synchronizer.h"
@@ -47,6 +48,7 @@
 #include "ui/aura/mus/window_tree_host_mus_init_params.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
+#include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/base/layout.h"
 #include "ui/base/ui_base_types.h"
@@ -1302,8 +1304,20 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
                                       window ? window->GetWindow() : nullptr);
   }
 
-  // TODO: use |display_id| to find host and send there.
+  // If the window has already been deleted, use |event| to update event states
+  // kept in aura::Env. Any WindowTreeHost should be okay to get
+  // aura::EnvInputStateController from since these are global states.

[sadrul, 2017/05/01 17:39:36]

Also, it may make sense to have Env own a single instance of
EnvInputStateController.

[riajiang, 2017/05/02 21:05:31]

Done in https://codereview.chromium.org/2854663002/.

   if (!window || !window->GetWindow()->GetHost()) {
+    DCHECK(!roots_.empty());
+    EnvInputStateController* env_controller =
+        GetWindowTreeHostMus(*roots_.begin())->dispatcher()->env_controller();

[sky, 2017/05/01 17:37:27]

How do you know roots_ is not empty here?

[riajiang, 2017/05/02 21:05:31]

Yes sorry didn't consider that case. Changed EnvInputStateController to be owned
by Env so we can get EnvInputStateController from Env here.

+    std::unique_ptr<ui::Event> mapped_event = MapEvent(*event.get());
+    if (mapped_event->IsMouseEvent()) {
+      env_controller->UpdateStateForMouseEvent(nullptr,
+                                               *mapped_event->AsMouseEvent());
+    } else if (mapped_event->IsTouchEvent()) {
+      env_controller->UpdateStateForTouchEvent(*mapped_event->AsTouchEvent());
+    }
     tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
     return;
   }