Add a first-class off-store install UI to chrome://extensions/.

chrome/browser/ui/webui/extensions/install_extension_handler.h

Index: chrome/browser/ui/webui/extensions/install_extension_handler.h
diff --git a/chrome/browser/ui/webui/extensions/install_extension_handler.h b/chrome/browser/ui/webui/extensions/install_extension_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..26aa349b70cf2c6dab83d76af1a99c5410c8327f
--- /dev/null
+++ b/chrome/browser/ui/webui/extensions/install_extension_handler.h
@@ -0,0 +1,48 @@
+// 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_WEBUI_EXTENSIONS_INSTALL_EXTENSION_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_EXTENSIONS_INSTALL_EXTENSION_HANDLER_H_
+#pragma once
+
+#include "base/file_path.h"
+#include "base/values.h"
+#include "content/public/browser/web_ui_message_handler.h"
+
+// Handles installing an extension when its file is dragged onto the page.
+class InstallExtensionHandler : public content::WebUIMessageHandler {
+ public:
+  InstallExtensionHandler();
+  virtual ~InstallExtensionHandler();
+
+  void GetLocalizedValues(DictionaryValue* localized_strings);
+
+  // WebUIMessageHandler implementation.
+  virtual void RegisterMessages() OVERRIDE;
+
+ private:
+  // Handles a notification from the JavaScript that a drag has started. This is
+  // needed so that we can capture the file being dragged. If we wait until
+  // we receive a drop notification, the drop data in the browser process will
+  // have already been destroyed.
+  void HandleStartDragMessage(const ListValue* args);
+
+  // Handles a notification from the JavaScript that a drag has stopped.
+  void HandleStopDragMessage(const ListValue* args);
+
+  // Handles a notification from the JavaScript to install the file currently
+  // being dragged.
+  //
+  // IMPORTANT: We purposefully do not allow the JavaScript to specify the file
+  // to be installed as a precaution against the extension management page
+  // getting XSS'd.
+  void HandleInstallMessage(const ListValue* args);
+
+  // The extension that will be installed when HandleInstallMessage() is called.
+  FilePath file_to_install_;
+
+  DISALLOW_COPY_AND_ASSIGN(InstallExtensionHandler);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_EXTENSIONS_INSTALL_EXTENSION_HANDLER_H_