Add sign in dialog for GCP->print preview integration.

chrome/browser/ui/webui/print_preview_handler.h

 // Copyright (c) 2011 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_PRINT_PREVIEW_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_HANDLER_H_
 #pragma once
 
 #include <string>
 
@@ skipping 75 matching lines @@
   // Second element of |args| is the current cloud print data JSON.
   void HandleSaveLastPrinter(const base::ListValue* args);
 
   // Gets the printer capabilities. First element of |args| is the printer name.
   void HandleGetPrinterCapabilities(const base::ListValue* args);
 
   // Asks the initiator renderer to show the native print system dialog. |args|
   // is unused.
   void HandleShowSystemDialog(const base::ListValue* args);
 
+  // Brings up a dialog to allow the user to sign into cloud print.
+  // |args| is unused.
+  void HandleSignin(const base::ListValue* args);
+
   // Brings up a web page to allow the user to configure cloud print.
   // |args| is unused.
   void HandleManageCloudPrint(const base::ListValue* args);
 
   // Reloads the initiator tab and closes the associated preview tab. |args| is
   // unused.
   void HandleReloadCrashedInitiatorTab(const base::ListValue* args);
 
   // Asks the browser to show the native printer management dialog.
   // |args| is unused.
@@ skipping 59 matching lines @@
   // Whether we have already logged a failed print preview.
   bool reported_failed_preview_;
 
   // Whether we have already logged the number of printers this session.
   bool has_logged_printers_count_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintPreviewHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_HANDLER_H_