Pepper: Add MonitorIsExternal function to PPB_Flash_DRM.

ppapi/cpp/private/flash_drm.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 PPAPI_CPP_PRIVATE_FLASH_DRM_H_
 #define PPAPI_CPP_PRIVATE_FLASH_DRM_H_
 
 #include "ppapi/cpp/completion_callback.h"
 #include "ppapi/cpp/file_ref.h"
 #include "ppapi/cpp/resource.h"
 
 namespace pp {
 
 class FileRef;
 
 namespace flash {
 
 class DRM : public Resource {
  public:
   DRM();
   explicit DRM(const InstanceHandle& instance);
 
   // On success, returns a string var.
   int32_t GetDeviceID(const CompletionCallbackWithOutput<Var>& callback);
   // Outputs the HMONITOR associated with the current plugin instance in
   // |hmonitor|. True is returned upon success.
   bool GetHmonitor(int64_t* hmonitor);
   // Returns the voucher file as a FileRef or an invalid resource on failure.
   int32_t GetVoucherFile(const CompletionCallbackWithOutput<FileRef>& callback);
+  // On success, returns a value indicating if the monitor associated with the
+  // current plugin instance is external.
+  int32_t MonitorIsExternal(
+      const CompletionCallbackWithOutput<PP_Bool>& callback);
 };
 
 }  // namespace flash
 }  // namespace pp
 
 #endif  // PPAPI_CPP_PRIVATE_FLASH_DRM_H_