Enabling forbid sync XHR in page dismissal by default.

Bug: 827324
Change-Id: Id12b26c1303a977081702e792b0bd8e3ecbd8012
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1542148
Commit-Queue: Katie Dillon <kdillon@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649921}
3 files changed