Make the PDF plugin respect the site's javascript content setting.

The PDF extension will now use the contentSettings extension API to
query the JavaScript content setting for the origin of a PDF document,
and pass that result into the plugin.

Bug: 696650
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I1419f403e815a4cc97f27bee4d8103b6b23639f4
Reviewed-on: https://chromium-review.googlesource.com/1055773
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562090}
6 files changed