Update policy parsing for ExtensionSettings, eliminate custom paths.

The initiator of a URLRequest only tracks the scheme, host, and port.
Being able to reliably block requests from a protected initiator is more
important than being able to block by path. This is needed to implement
changes to chrome.webRequest which block event dispatches based on initiator https://codereview.chromium.org/2495353003/.

Bug: 624649
Change-Id: I20e8e6543924e1001908d7268c2490a45485987e
Reviewed-on: https://chromium-review.googlesource.com/517228
Commit-Queue: Nick Peterson <nrpeter@google.com>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#476995}
6 files changed