Attempt to re-land FocusManager removal from Aura.

ui/aura/test/test_focus_client.cc

+// Copyright 2013 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 "ui/aura/test/test_focus_client.h"
+
+#include "ui/aura/client/focus_change_observer.h"
+#include "ui/aura/window.h"
+
+namespace aura {
+namespace test {
+
+////////////////////////////////////////////////////////////////////////////////
+// TestFocusClient, public:
+
+TestFocusClient::TestFocusClient()
+    : focused_window_(NULL),
+      observer_manager_(this) {
+}
+
+TestFocusClient::~TestFocusClient() {
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TestFocusClient, client::FocusClient implementation:
+
+void TestFocusClient::AddObserver(client::FocusChangeObserver* observer) {
+}
+
+void TestFocusClient::RemoveObserver(client::FocusChangeObserver* observer) {
+}
+
+void TestFocusClient::FocusWindow(Window* window) {
+  if (window && !window->CanFocus())
+    return;
+  if (focused_window_)
+    observer_manager_.Remove(focused_window_);
+  aura::Window* old_focused_window = focused_window_;
+  focused_window_ = window;
+  if (focused_window_)
+    observer_manager_.Add(focused_window_);
+
+  client::FocusChangeObserver* observer =
+      client::GetFocusChangeObserver(old_focused_window);
+  if (observer)
+    observer->OnWindowFocused(focused_window_, old_focused_window);
+  observer = client::GetFocusChangeObserver(focused_window_);
+  if (observer)
+    observer->OnWindowFocused(focused_window_, old_focused_window);
+}
+
+void TestFocusClient::ResetFocusWithinActiveWindow(Window* window) {
+  if (!window->Contains(focused_window_))
+    FocusWindow(window);
+}
+
+Window* TestFocusClient::GetFocusedWindow() {
+  return focused_window_;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TestFocusClient, WindowObserver implementation:
+
+void TestFocusClient::OnWindowDestroying(Window* window) {
+  DCHECK_EQ(window, focused_window_);
+  FocusWindow(NULL);
+}
+
+}  // namespace test
+}  // namespace aura