Roll WebRTC 18004:18018 (10 commits)

Changes: https://chromium.googlesource.com/external/webrtc/trunk/webrtc.git/+log/075011d..211c500

$ git log 075011d..211c500 --date=short --no-merges --format=%ad %ae %s
2017-05-04 philipel@webrtc.org Don't initiate perodic probing if we don't have a bandwidth estimate.
2017-05-04 pbos@webrtc.org Remove layer_sync from TL frame config.
2017-05-04 henrik.lundin@webrtc.org NetEqTest: Extend the callback structure
2017-05-04 sakal@webrtc.org Add functionality to clear surface to a specific color in EglRenderer.
2017-05-04 pbos@webrtc.org Derive current layer from TL frame config.
2017-05-04 magjed@webrtc.org Reland of Move CoreVideoFrameBuffer from webrtc/common_video/ to webrtc/sdk/objc/ (patchset #1 id:1 of https://codereview.webrtc.org/2862663003/ )
2017-05-04 oprypin@webrtc.org Add --quick flag to low bandwidth audio test
2017-05-04 sprang@webrtc.org Update decode/render fps stats when calling VideoReceiveStream::GetStats
2017-05-04 nisse@webrtc.org Revert of Delete deprecated and transitional stuff related to video frame refactoring. (patchset #1 id:1 of https://codereview.webrtc.org/2854873003/ )
2017-05-04 nisse@webrtc.org Reland of Delete deprecated and transitional stuff related to video frame refactoring. (patchset #1 id:1 of https://codereview.webrtc.org/2854883002/ )

TBR=
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_archive_rel_ng;master.tryserver.chromium.mac:mac_chromium_archive_rel_ng

Review-Url: https://codereview.chromium.org/2862723003
Cr-Commit-Position: refs/heads/master@{#469407}

DEPS

@@ -235,7 +235,7 @@ deps = {
     Var('chromium_git') + '/native_client/src/third_party/scons-2.0.1.git' + '@' + '1c1550e17fc26355d08627fbdec13d8291227067',
 
   'src/third_party/webrtc':
-    Var('chromium_git') + '/external/webrtc/trunk/webrtc.git' + '@' + '075011de8950652184fdf32dcd60a6ce888166aa', # commit position 18004
+    Var('chromium_git') + '/external/webrtc/trunk/webrtc.git' + '@' + '211c50088df09f0c99560b8ceb44a4971f68ff67', # commit position 18018
 
   'src/third_party/openmax_dl':
     Var('chromium_git') + '/external/webrtc/deps/third_party/openmax.git' + '@' +  Var('openmax_dl_revision'),