Refactor ShellWindow to separate platform-specific code.

chrome/browser/ui/extensions/native_shell_window.h

+// Copyright (c) 2012 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 CHROME_BROWSER_UI_EXTENSIONS_NATIVE_SHELL_WINDOW_H_
+#define CHROME_BROWSER_UI_EXTENSIONS_NATIVE_SHELL_WINDOW_H_
+
+#include "chrome/browser/ui/extensions/shell_window.h"
+#include "chrome/browser/ui/base_window.h"
+
+// This is an interface to a native implementation of a shell window, used for
+// new-style packaged apps. Shell windows contain a web contents, but no tabs
+// or URL bar.
+class NativeShellWindow : public BaseWindow {
+ public:
+  // Used by ShellWindow to instantiate the platform-specific ShellWindow code.
+  static NativeShellWindow* Create(ShellWindow* window,
+                                   const ShellWindow::CreateParams& params);
+
+  // Called when the title of the window changes.
+  virtual void UpdateWindowTitle() = 0;
+
+  // Called when the draggable regions are changed.
+  virtual void UpdateDraggableRegions(
+      const std::vector<extensions::DraggableRegion>& regions) {}
+
+  virtual void SetFullscreen(bool fullscreen) = 0;
+  virtual bool IsFullscreenOrPending() const = 0;
+
+  virtual ~NativeShellWindow() {}
+};
+
+#endif  // CHROME_BROWSER_UI_EXTENSIONS_NATIVE_SHELL_WINDOW_H_