Remove MessageLoop::current() usage in /content/browser/devtools

Replacing it with modern RunLoop+QuitClosure usage.

R=caseq@chromium.org

Bug: 825327
Change-Id: I43e021d3a3c5e76923e77c8d28560931dc3ee866
Reviewed-on: https://chromium-review.googlesource.com/1024445
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553699}
1 file changed