Roll src/third_party/webrtc a4c1aaad8d5f..26f7dde56c90 (6 commits)

https://webrtc.googlesource.com/src.git/+log/a4c1aaad8d5f..26f7dde56c90

git log a4c1aaad8d5f..26f7dde56c90 --date=short --no-merges --format='%ad %ae %s'
2019-11-11 mbonadei@webrtc.org Revert "Whitespace change"
2019-11-11 alessiob@webrtc.org APM runtime setting: fix kPlayoutVolumeChange not dispatched
2019-11-11 chromium-webrtc-autoroll@webrtc-ci.iam.gserviceaccount.com Roll chromium_revision 5145d23f..e2cf3bc0 (714086:714186)
2019-11-11 philipel@webrtc.org Add allowCodecSwitching flag to RTCConfiguration.mm
2019-11-11 mbonadei@webrtc.org Whitespace change
2019-11-11 asapersson@webrtc.org Add field trial for rampup in quality based on available bandwidth.

Created with:
  gclient setdep -r src/third_party/webrtc@26f7dde56c90

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/webrtc-chromium-autoroll
Please CC webrtc-chromium-sheriffs-robots@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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

TBR=webrtc-chromium-sheriffs-robots@google.com

Bug: chromium:None,chromium:None,chromium:None,chromium:none
Change-Id: Ia447ff234f35bbb597531725a443fb25ab304a63
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1910167Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#714264}

DEPS

@@ -1484,7 +1484,7 @@ deps = {
     Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + 'dd55f3ca8f2ea716ca917a4aaf36f0729fe902b1',
 
   'src/third_party/webrtc':
-    Var('webrtc_git') + '/src.git' + '@' + 'a4c1aaad8d5fe0d412f08f084b0aa36e01393550',
+    Var('webrtc_git') + '/src.git' + '@' + '26f7dde56c900ec3b7f40289df1d65ca9a9afbfc',
 
   # Wuffs' canonical repository is at github.com/google/wuffs, but we use
   # Skia's mirror of Wuffs, the same as in upstream Skia's DEPS file.