mus: Introduce API for embedder to dispatch event to the embeded client.

ash/mus/window_manager_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 <stdint.h>
 
 #include <memory>
 #include <utility>
 
 #include "ash/public/interfaces/user_window_controller.mojom.h"
@@ skipping 26 matching lines @@
 
 class WindowManagerTest : public shell::test::ShellTest {
  public:
   WindowManagerTest() : shell::test::ShellTest("exe:mash_unittests") {}
   ~WindowManagerTest() override {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WindowManagerTest);
 };
 
-void OnEmbed(bool success) {
+void OnEmbed(bool success, ::mus::mojom::InputEventHandlerPtr handler) {
   ASSERT_TRUE(success);
 }
 
 class TestUserWindowObserver : public mojom::UserWindowObserver {
  public:
   explicit TestUserWindowObserver(shell::Connector* connector)
       : binding_(this), window_count_(0u), expected_window_count_(0u) {
     connector->ConnectToInterface("mojo:ash", &user_window_controller_);
     user_window_controller_->AddUserWindowObserver(
         binding_.CreateInterfacePtrAndBind());
@@ skipping 66 matching lines @@
   ::mus::Window* top_level_window = client->NewTopLevelWindow(nullptr);
   ASSERT_TRUE(top_level_window);
   ::mus::Window* child_window = client->NewWindow();
   ASSERT_TRUE(child_window);
   top_level_window->AddChild(child_window);
 
   // Create another WindowTreeClient by way of embedding in
   // |child_window|. This blocks until it succeeds.
   ::mus::mojom::WindowTreeClientPtr tree_client;
   auto tree_client_request = GetProxy(&tree_client);
-  child_window->Embed(std::move(tree_client), base::Bind(&OnEmbed));
+  child_window->Embed(std::move(tree_client));
   std::unique_ptr<::mus::WindowTreeClient> child_client(
       new ::mus::WindowTreeClient(&window_tree_delegate, nullptr,
                                   std::move(tree_client_request)));
   child_client->WaitForEmbed();
   ASSERT_TRUE(!child_client->GetRoots().empty());
 }
 
 TEST_F(WindowManagerTest, OpenWindowAndClose) {
   connector()->Connect("mojo:ash");
 
   TestUserWindowObserver observer(connector());
 
   // Connect to mus and create a new top level window.
   WindowTreeClientDelegate window_tree_delegate;
   std::unique_ptr<::mus::WindowTreeClient> client(
       new ::mus::WindowTreeClient(&window_tree_delegate, nullptr, nullptr));
   client->ConnectViaWindowTreeFactory(connector());
   ::mus::Window* top_level_window = client->NewTopLevelWindow(nullptr);
   ASSERT_TRUE(top_level_window);
 
   observer.WaitUntilWindowCountReaches(1u);
   client.reset();
   observer.WaitUntilWindowCountReaches(0u);
 }
 
 }  // namespace mus
 }  // namespace ash