mus: Add EventObserver to allow passively listening to UI events

components/mus/public/cpp/tests/window_tree_client_impl_unittest.cc

 // Copyright 2015 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 <stdint.h>
 
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 447 matching lines @@
   Window* root = setup.GetFirstRoot();
   ASSERT_TRUE(root);
 
   TestInputEventHandler event_handler;
   root->set_input_event_handler(&event_handler);
 
   std::unique_ptr<ui::Event> ui_event(
       new ui::MouseEvent(ui::ET_MOUSE_MOVED, gfx::Point(), gfx::Point(),
                          ui::EventTimeForNow(), ui::EF_NONE, 0));
   setup.window_tree_client()->OnWindowInputEvent(
-      1, server_id(root), mojom::Event::From(*ui_event.get()));
+      1, server_id(root), mojom::Event::From(*ui_event.get()), false);
   EXPECT_TRUE(event_handler.received_event());
   EXPECT_TRUE(setup.window_tree()->WasEventAcked(1));
   event_handler.Reset();
 
   event_handler.set_should_manually_ack();
   setup.window_tree_client()->OnWindowInputEvent(
-      33, server_id(root), mojom::Event::From(*ui_event.get()));
+      33, server_id(root), mojom::Event::From(*ui_event.get()), false);
   EXPECT_TRUE(event_handler.received_event());
   EXPECT_FALSE(setup.window_tree()->WasEventAcked(33));
 
   event_handler.AckEvent();
   EXPECT_TRUE(setup.window_tree()->WasEventAcked(33));
 }
 
 // Verifies focus is reverted if the server replied that the change failed.
 TEST_F(WindowTreeClientImplTest, SetFocusFailed) {
   WindowTreeSetup setup;
@@ skipping 435 matching lines @@
 
   setup.window_tree_client()->OnChangeCompleted(change_id2, false);
   EXPECT_FALSE(child->HasCapture());
   EXPECT_TRUE(root->HasCapture());
 
   setup.window_tree_client()->OnLostCapture(server_id(root));
   EXPECT_FALSE(root->HasCapture());
 }
 
 }  // namespace mus