Roll chromium_revision de13cf4..28d1981 (299488:300483)

Mainly to pick up https://codereview.chromium.org/656293004/
to fix some MSan issues.

Summary of changes (https://chromium.googlesource.com/chromium/src/+/de13cf4..28d1981/DEPS):
* third_party/android_tools d2b8620..36bf7ac
* third_party/libyuv 455c66b..5a09c3e (1038:1130)
* third_party/usrsctp/usrsctplib a11b3c5..7accb99
* tools/gyp 1977:1990
* tools/swarming_client c28b74f..a57d7db

Clang updated 217949:218707 (git diff de13cf4..28d1981 tools/clang/scripts/update.sh)

R=pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/31759004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7489 4adac7df-926f-26a2-2b94-8c16560cd09d