Added functionality to use "SaveAs..." from PDF plugin.

chrome/common/render_messages.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.
 
 // Multiply-included file, no traditional include guard.
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 470 matching lines @@
                     int32 /* page_id */,
                     bool  /* result */)
 
 // Updates the content restrictions, i.e. to disable print/copy.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_UpdateContentRestrictions,
                     int /* restrictions */)
 
 // The currently displayed PDF has an unsupported feature.
 IPC_MESSAGE_ROUTED0(ViewHostMsg_PDFHasUnsupportedFeature)
 
+// Brings up SaveAs... dialog (similar to the wrench->SaveAs...).
+IPC_MESSAGE_ROUTED0(ViewHostMsg_SaveAs)
+
 // JavaScript related messages -----------------------------------------------
 
 // Notify the JavaScript engine in the render to change its parameters
 // while performing stress testing.
 IPC_MESSAGE_ROUTED2(ViewMsg_JavaScriptStressTestControl,
                     int /* cmd */,
                     int /* param */)
 
 // Register a new handler for URL requests with the given scheme.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_RegisterProtocolHandler,
                     std::string /* scheme */,
                     GURL /* url */,
                     string16 /* title */)