Add an API to Pause and Resume background offlining requests.

components/offline_pages/background/request_picker.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/offline_pages/background/request_picker.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "components/offline_pages/background/save_page_request.h"
 
@@ skipping 103 matching lines @@
   if (request.started_attempt_count() >= policy_->GetMaxStartedTries())
     return false;
 
   // If we have already completed trying this page the max number of times, it
   // is not eligible to try again.
   // TODO(petewil): We should have code to remove the page from the
   // queue after the last retry.
   if (request.completed_attempt_count() >= policy_->GetMaxCompletedTries())
     return false;
 
+  // If the request is paused, do not consider it.
+  if (request.request_state() == SavePageRequest::RequestState::PAUSED)
+    return false;
+
   // If the request is expired, do not consider it.
   // TODO(petewil): We need to remove this from the queue.
   base::TimeDelta requestAge = base::Time::Now() - request.creation_time();
   if (requestAge >
       base::TimeDelta::FromSeconds(
           policy_->GetRequestExpirationTimeInSeconds()))
     return false;
 
   // If this request is not active yet, return false.
   // TODO(petewil): If the only reason we return nothing to do is that we have
@@ skipping 79 matching lines @@
   int result = signum(difference.InMilliseconds());
 
   // Flip the direction of comparison if policy prefers fewer retries.
   if (earlier_requests_better_)
     result *= -1;
 
   return result;
 }
 
 }  // namespace offline_pages