Removed NativeMetafile and PreviewMetafile typedef as it's always PdfMetafileSkia.

chrome/common/print_messages.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.
 
 // IPC messages for printing.
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
@@ skipping 382 matching lines @@
 // by javascript. This step is about showing UI to the user to select the
 // final print settings. The output parameter is the same as
 // ViewMsg_PrintPages which is executed implicitly.
 IPC_SYNC_MESSAGE_ROUTED1_1(PrintHostMsg_ScriptedPrint,
                            PrintHostMsg_ScriptedPrint_Params,
                            PrintMsg_PrintPages_Params
                                /* settings chosen by the user*/)
 
 #if defined(OS_CHROMEOS) || defined(OS_ANDROID)
 // Asks the browser to create a temporary file for the renderer to fill
-// in resulting NativeMetafile in printing.
+// in resulting PdfMetafileSkia in printing.
 IPC_SYNC_MESSAGE_CONTROL1_2(PrintHostMsg_AllocateTempFileForPrinting,
                             int /* render_view_id */,
                             base::FileDescriptor /* temp file fd */,
                             int /* fd in browser*/) // Used only by Chrome OS.
 IPC_MESSAGE_CONTROL2(PrintHostMsg_TempFileForPrintingWritten,
                      int /* render_view_id */,
                      int /* fd in browser */) // Used only by Chrome OS.
 #endif
 
 // Asks the browser to do print preview.
@@ skipping 56 matching lines @@
 IPC_SYNC_MESSAGE_ROUTED0_0(PrintHostMsg_SetupScriptedPrintPreview)
 
 // Tell the browser to show the print preview, when the document is sufficiently
 // loaded such that the renderer can determine whether it is modifiable or not.
 IPC_MESSAGE_ROUTED1(PrintHostMsg_ShowScriptedPrintPreview,
                     bool /* is_modifiable */)
 
 // Notify the browser to set print presets based on source PDF document.
 IPC_MESSAGE_ROUTED1(PrintHostMsg_SetOptionsFromDocument,
                     PrintHostMsg_SetOptionsFromDocument_Params /* params */)