chromeos: make InputMethodMus ack events when resetting connection

Now that we reset the connection when nothing is focused we need to ack
any pending events.

BUG=681563
TEST=covered by test

Change-Id: I1fc3219a04a49f911434ea8def7d9eca223c4ab6
Reviewed-on: https://chromium-review.googlesource.com/1089885Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565100}

services/ui/ws2/window_service_client.cc

@@ -1274,6 +1274,8 @@ void WindowServiceClient::OnWindowInputEventAck(uint32_t event_id,
       window_service_->delegate()->OnUnhandledKeyEvent(
           *(in_flight_event->event->AsKeyEvent()));
     }
+  } else if (event_id != kDefaultEventId) {
+    DVLOG(1) << "OnWindowInputEventAck supplied unexpected id " << event_id;
   }
 }
 

ui/aura/mus/input_method_mus.cc

@@ -150,6 +150,11 @@ void InputMethodMus::OnDidChangeFocusedClient(
   InputMethodBase::OnDidChangeFocusedClient(focused_before, focused);
   UpdateTextInputType();
 
+  // We are about to close the pipe with pending callbacks. Closing the pipe
+  // results in none of the callbacks being run. We have to run the callbacks
+  // else mus won't process the next event immediately.
+  AckPendingCallbacksUnhandled();
+
   if (!focused) {
     input_method_ = nullptr;
     input_method_ptr_.reset();
@@ -160,11 +165,6 @@ void InputMethodMus::OnDidChangeFocusedClient(
   text_input_client_ =
       std::make_unique<TextInputClientImpl>(focused, delegate());
 
-  // We are about to close the pipe with pending callbacks. Closing the pipe
-  // results in none of the callbacks being run. We have to run the callbacks
-  // else mus won't process the next event immediately.
-  AckPendingCallbacksUnhandled();
-
   if (ime_driver_) {
     ui::mojom::StartSessionDetailsPtr details =
         ui::mojom::StartSessionDetails::New();

ui/aura/mus/input_method_mus_unittest.cc

@@ -158,6 +158,35 @@ TEST_F(InputMethodMusTest, PendingCallbackRunFromOnDidChangeFocusedClient) {
   EXPECT_TRUE(was_event_result_callback_run);
 }
 
+TEST_F(InputMethodMusTest,
+       PendingCallbackRunFromOnDidChangeFocusedClientToNull) {
+  aura::Window window(nullptr);
+  window.Init(ui::LAYER_NOT_DRAWN);
+  bool was_event_result_callback_run = false;
+  // Create an InputMethodMus and foward an event to it.
+  TestInputMethodDelegate input_method_delegate;
+  InputMethodMus input_method_mus(&input_method_delegate, &window);
+  TestInputMethod test_input_method;
+  InputMethodMusTestApi::SetInputMethod(&input_method_mus, &test_input_method);
+  EventResultCallback callback = base::BindOnce(&RunFunctionWithEventResult,
+                                                &was_event_result_callback_run);
+  ui::EventDispatchDetails details =
+      InputMethodMusTestApi::CallSendKeyEventToInputMethod(
+          &input_method_mus,
+          ui::KeyEvent(ui::ET_KEY_PRESSED, ui::VKEY_RETURN, 0),
+          std::move(callback));
+  ASSERT_TRUE(!details.dispatcher_destroyed && !details.target_destroyed);
+  // The event should have been queued.
+  EXPECT_EQ(1u, test_input_method.process_key_event_callbacks()->size());
+  // Callback should not have been run yet.
+  EXPECT_FALSE(was_event_result_callback_run);
+
+  InputMethodMusTestApi::CallOnDidChangeFocusedClient(&input_method_mus,
+                                                      nullptr, nullptr);
+  // Changing the focused client should trigger running the callback.
+  EXPECT_TRUE(was_event_result_callback_run);
+}
+
 // See description of ChangeTextInputTypeWhileProcessingCallback for details.
 class TestInputMethodDelegate2 : public ui::internal::InputMethodDelegate {
  public: