Manual changes:
* Rewrite sysroot download (similar to https://webrtc-review.googlesource.com/c/50183/)
* Do the same as https://webrtc-review.googlesource.com/c/21400/.
* Add dep on findbugs for Android.

Change log: https://chromium.googlesource.com/chromium/src/+log/ff3b31782d..80f0c55706
Full diff: https://chromium.googlesource.com/chromium/src/+/ff3b31782d..80f0c55706

Changed dependencies:
* src/base: https://chromium.googlesource.com/chromium/src/base/+log/9b543d487c..ac3d2b8118
* src/build: https://chromium.googlesource.com/chromium/src/build/+log/156ba982d7..39738e75b2
* src/buildtools: https://chromium.googlesource.com/chromium/buildtools.git/+log/f6d165d9d8..a09e064635
* src/ios: https://chromium.googlesource.com/chromium/src/ios/+log/39c4b2fcf7..299ef76e84
* src/testing: https://chromium.googlesource.com/chromium/src/testing/+log/cc96d3d66b..5f7e36cad6
* src/third_party: https://chromium.googlesource.com/chromium/src/third_party/+log/72c52c224c..2c0ced3ddb
* src/third_party/android_tools: https://chromium.googlesource.com/android_tools.git/+log/aadb2fed04..9a70d48fcd
* src/third_party/catapult: https://chromium.googlesource.com/catapult.git/+log/aa736cc76e..e7298f36f7
* src/third_party/googletest/src: https://chromium.googlesource.com/external/github.com/google/googletest.git/+log/7f8fefabed..0062e4869f
* src/third_party/icu: https://chromium.googlesource.com/chromium/deps/icu.git/+log/08cb956852..d888fd2a1b
* src/third_party/robolectric/robolectric: https://chromium.googlesource.com/external/robolectric.git/+log/b02c65cc6d..7e067f1112
* src/tools: https://chromium.googlesource.com/chromium/src/tools/+log/eceb2c420b..6202b67fc4
* src/tools/swarming_client: https://chromium.googlesource.com/infra/luci/client-py.git/+log/5e8001d9a7..88229872dd
DEPS diff: https://chromium.googlesource.com/chromium/src/+/ff3b31782d..80f0c55706/DEPS

Clang version changed 313786:324578
Details: https://chromium.googlesource.com/chromium/src/+/ff3b31782d..80f0c55706/tools/clang/scripts/update.py

BUG=libyuv:768

Rewrite sysroot download

Change-Id: Ie3cb0ba873c6c40877870b655ed299450726eac2
Reviewed-on: https://chromium-review.googlesource.com/918461Reviewed-by: Frank Barchard <fbarchard@chromium.org>
Commit-Queue: Patrik Höglund <phoglund@chromium.org>