Roll src/third_party/webrtc 6e250820b17e..7a1c7f782a14 (6 commits)

https://webrtc.googlesource.com/src.git/+log/6e250820b17e..7a1c7f782a14


git log 6e250820b17e..7a1c7f782a14 --date=short --no-merges --format='%ad %ae %s'
2018-08-01 hta@webrtc.org Modified peerconnection's "observer" slot to be nulled on close.
2018-08-01 kthelgason@webrtc.org Support compiling with the lastest iOS SDK.
2018-08-01 alessiob@webrtc.org RNN VAD: more specific build target names.
2018-08-01 peterhanspers@webrtc.org The pixel buffer pool is currently recreated on every call to encode.
2018-08-01 kthelgason@webrtc.org Include RTCMTLVideoView even on archs without metal.
2018-08-01 nisse@webrtc.org Reland "Delete root header file typedefs.h. Part 2."


Created with:
  gclient setdep -r src/third_party/webrtc@7a1c7f782a14

The AutoRoll server is located here: https://webrtc-chromium-roll.skia.org

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=luci.chromium.try:linux_chromium_archive_rel_ng;master.tryserver.chromium.mac:mac_chromium_archive_rel_ng

BUG=chromium:868337,chromium:None
TBR=webrtc-chromium-sheriffs-robots@google.com

Change-Id: I6e2ac484f7508ffc83bec8414a94d4905e7f0f3b
Reviewed-on: https://chromium-review.googlesource.com/1158347Reviewed-by: webrtc-chromium-autoroll <webrtc-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: webrtc-chromium-autoroll <webrtc-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#579817}

DEPS

@@ -1034,7 +1034,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '21dbf06b5aa6c7dc8cf56314d4a3f96f57956c53',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + '6e250820b17ef1833da52948426a55ae075c6094',
+    Var('webrtc_git') + '/src.git' + '@' + '7a1c7f782a149a688e4d74f4df90b10185c01724',
 
   'src/third_party/xdg-utils': {
       'url': Var('chromium_git') + '/chromium/deps/xdg-utils.git' + '@' + 'd80274d5869b17b8c9067a1022e4416ee7ed5e0d',