Introduces AppActivity and handler of chrome.shell API.

apps/shell/browser/default_shell_app_window_controller.cc

Index: apps/shell/browser/default_shell_app_window_controller.cc
diff --git a/apps/shell/browser/default_shell_app_window_controller.cc b/apps/shell/browser/default_shell_app_window_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3ec5b6bc848ee067ba4af2efb9f48196de34864b
--- /dev/null
+++ b/apps/shell/browser/default_shell_app_window_controller.cc
@@ -0,0 +1,45 @@
+// Copyright 2014 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 "apps/shell/browser/default_shell_app_window_controller.h"
+
+#include "apps/shell/browser/shell_app_window.h"
+#include "apps/shell/browser/shell_desktop_controller.h"
+#include "base/logging.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_tree_host.h"
+
+namespace apps {
+
+DefaultShellAppWindowController::DefaultShellAppWindowController(
+    ShellDesktopController* shell_desktop_controller)
+    : shell_desktop_controller_(shell_desktop_controller) {
+  DCHECK(shell_desktop_controller_);
+}
+
+DefaultShellAppWindowController::~DefaultShellAppWindowController() {
+  // The app window must be explicitly closed before desktop teardown.
+  DCHECK(!app_window_);
+}
+
+ShellAppWindow* DefaultShellAppWindowController::CreateAppWindow(
+    content::BrowserContext* context) {
+  aura::Window* root_window = shell_desktop_controller_->host()->window();
+
+  app_window_.reset(new ShellAppWindow);
+  app_window_->Init(context, root_window->bounds().size());
+
+  // Attach the web contents view to our window hierarchy.
+  aura::Window* content = app_window_->GetNativeWindow();
+  root_window->AddChild(content);
+  content->Show();
+
+  return app_window_.get();
+}
+
+void DefaultShellAppWindowController::CloseAppWindows() {
+  app_window_.reset();
+}
+
+}  // namespace apps