The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/91f93ff1742c76686413531ec1f6a5214b833bd5

commit 91f93ff1742c76686413531ec1f6a5214b833bd5
Author: romax <romax@chromium.org>
Date: Thu Aug 18 20:49:18 2016

[Offline Pages] Remove expired requests from the queue.

Added logic to remove expired requests from the queue when picking next
requests. Also added a placeholder for notification through coordinator.

BUG= 636185 

Review-Url: https://codereview.chromium.org/2233493003
Cr-Commit-Position: refs/heads/master@{#412926}

[modify] https://crrev.com/91f93ff1742c76686413531ec1f6a5214b833bd5/components/offline_pages/background/request_coordinator.cc
[modify] https://crrev.com/91f93ff1742c76686413531ec1f6a5214b833bd5/components/offline_pages/background/request_coordinator.h
[add] https://crrev.com/91f93ff1742c76686413531ec1f6a5214b833bd5/components/offline_pages/background/request_notifier.h
[modify] https://crrev.com/91f93ff1742c76686413531ec1f6a5214b833bd5/components/offline_pages/background/request_picker.cc
[modify] https://crrev.com/91f93ff1742c76686413531ec1f6a5214b833bd5/components/offline_pages/background/request_picker.h
[modify] https://crrev.com/91f93ff1742c76686413531ec1f6a5214b833bd5/components/offline_pages/background/request_picker_unittest.cc