Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/9cde9c9..87eca92

Rolling v8/tools/clang: https://chromium.googlesource.com/chromium/src/tools/clang/+log/0ec6dce..5b3c04d

TBR=machenbach@chromium.org,vogelheim@chromium.org,hablich@chromium.org

Review-Url: https://codereview.chromium.org/2619503002
Cr-Commit-Position: refs/heads/master@{#42104}