Enable 64 bit truncation warnings in blink

BUG=879657

Change-Id: I80f12446a4a7507436fa85db4b454705b841a91b
Reviewed-on: https://chromium-review.googlesource.com/c/1362207
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621694}
1 file changed