Roll src/third_party/ffmpeg 2ab535183..2f698edc4 (1 commit)

This updates ffmpeg to work around a VC++ 2015 Update 1 code-gen bug.

https://chromium.googlesource.com/chromium/third_party/ffmpeg.git/+log/2ab535183e2f..2f698edc4eb0

2016-01-28 brucedawson Workaround VC++ 2015 Update 1 code-gen bug

TBR=dalecurtis@chromium.org
BUG=581768,440500

Review URL: https://codereview.chromium.org/1642053003

Cr-Commit-Position: refs/heads/master@{#372178}

DEPS

@@ -184,7 +184,7 @@ deps = {
    Var('chromium_git') + '/webm/libvpx.git' + '@' +  'd6996849f0c65b97c40318647c3e7dc2db332861',
 
   'src/third_party/ffmpeg':
-   Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + '2ab535183e2fca15d37be86bf0edf5aa8c6767cf',
+   Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + '2f698edc4eb0819432c332508c15c0aec374bea2',
 
   'src/third_party/libjingle/source/talk':
     Var('chromium_git') + '/external/webrtc/trunk/talk.git' + '@' + '420a246d446c65c44896c5cdda2c0629a8b506dd', # commit position 11412