Merge to M39: Add extra checks to avoid integer overflow.

BUG=425980
TEST=no crash with ASAN

Review URL: https://codereview.chromium.org/659743004

Cr-Commit-Position: refs/heads/master@{#301249}
(cherry picked from commit b2006ac87cec58363090e7d5e10d5d9e3bbda9f9)

R=xhwang@chromium.org

Review URL: https://codereview.chromium.org/695673002

Cr-Commit-Position: refs/branch-heads/2171@{#312}
Cr-Branched-From: 267aeeb8d85c8503a7fd12bd14654b8ea78d3974-refs/heads/master@{#297060}
1 file changed