Revert of RTCRtpReceiver.getContributingSources() added.

third_party/WebKit/Source/platform/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//third_party/WebKit/public/public_features.gni")
 import("//third_party/WebKit/Source/build/scripts/scripts.gni")
@@ skipping 532 matching lines @@
     "exported/WebPrerender.cpp",
     "exported/WebPrerenderingSupport.cpp",
     "exported/WebPresentationAvailabilityObserver.cpp",
     "exported/WebPresentationConnection.cpp",
     "exported/WebPresentationConnectionCallbacks.cpp",
     "exported/WebPresentationController.cpp",
     "exported/WebPresentationReceiver.cpp",
     "exported/WebRTCAnswerOptions.cpp",
     "exported/WebRTCICECandidate.cpp",
     "exported/WebRTCOfferOptions.cpp",
-    "exported/WebRTCRtpContributingSource.cpp",
     "exported/WebRTCRtpReceiver.cpp",
     "exported/WebRTCSessionDescription.cpp",
     "exported/WebRTCSessionDescriptionRequest.cpp",
     "exported/WebRTCStats.cpp",
     "exported/WebRTCStatsRequest.cpp",
     "exported/WebRTCStatsResponse.cpp",
     "exported/WebRTCVoidRequest.cpp",
     "exported/WebScrollbarImpl.cpp",
     "exported/WebScrollbarImpl.h",
     "exported/WebScrollbarThemeClientImpl.cpp",
@@ skipping 1598 matching lines @@
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:inside_blink",
   ]
 
   deps = [
     ":test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }