Introduces AppActivity and handler of chrome.shell API.

apps/shell/browser/default_shell_app_window_controller.h

Index: apps/shell/browser/default_shell_app_window_controller.h
diff --git a/apps/shell/browser/default_shell_app_window_controller.h b/apps/shell/browser/default_shell_app_window_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..36dccd834dd439aa28302098a62facb451aca924
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+++ b/apps/shell/browser/default_shell_app_window_controller.h
@@ -0,0 +1,40 @@
+// 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.
+
+#ifndef APPS_SHELL_BROWSER_DEFAULT_SHELL_APP_WINDOW_CONTROLLER_H_
+#define APPS_SHELL_BROWSER_DEFAULT_SHELL_APP_WINDOW_CONTROLLER_H_
+
+#include "apps/shell/browser/shell_app_window_controller.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace apps {
+
+class ShellDesktopController;
+
+// The default shell app window controller for app_shell.  It manages only one
+// app_window.
+class DefaultShellAppWindowController : public ShellAppWindowController {
+ public:
+  explicit DefaultShellAppWindowController(
+      ShellDesktopController* shell_desktop_controller);
+  virtual ~DefaultShellAppWindowController();
+
+  // ShellAppWindowController implementation.
+  virtual ShellAppWindow* CreateAppWindow(
+      content::BrowserContext* context) OVERRIDE;
+  virtual void CloseAppWindows() OVERRIDE;
+
+ private:
+  ShellDesktopController* shell_desktop_controller_;  // Not owned
+
+  // The desktop supports a single app window.
+  scoped_ptr<ShellAppWindow> app_window_;
+
+  DISALLOW_COPY_AND_ASSIGN(DefaultShellAppWindowController);
+};
+
+}  // namespace apps
+
+#endif  // APPS_SHELL_BROWSER_DEFAULT_SHELL_APP_WINDOW_CONTROLLER_H_