[DevTools] ignore empty lines when searching for breakpoint location

R=lushnikov@chromium.org

Bug: chromium:784852
Change-Id: If45209a8caf48068b6c612ccfd169035af5e63f1
Reviewed-on: https://chromium-review.googlesource.com/794752
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Andrey Lushnikov <lushnikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520325}
3 files changed