Add CreateWindowCapturer() and CreateScreenCapturer() in DesktopCapturer

webrtc/modules/desktop_capture/screen_capturer_x11.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 406 matching lines @@
     return nullptr;
   }
 
   if (options.detect_updated_region()) {
     capturer.reset(new ScreenCapturerDifferWrapper(std::move(capturer)));
   }
 
   return capturer.release();
 }
 
+// static
+std::unique_ptr<DesktopCapturer> DesktopCapturer::CreateRawScreenCapturer(
+    const DesktopCaptureOptions& options) {
+  if (!options.x_display())
+    return nullptr;
+
+  std::unique_ptr<ScreenCapturer> capturer(new ScreenCapturerLinux());
+  if (!static_cast<ScreenCapturerLinux*>(capturer.get())->Init(options)) {
+    return nullptr;
+  }
+
+  return capturer;
+}
+
 }  // namespace webrtc