[Offline Pages] Adds event logs for requests dropped due to number of start or complete attempts.

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"
 
 namespace {
 template <typename T>
 int signum(T t) {
   return (T(0) < t) - (t < T(0));
 }
 
-#define CALL_MEMBER_FUNCTION(object,ptrToMember)  ((object)->*(ptrToMember))
+#define CALL_MEMBER_FUNCTION(object, ptrToMember) ((object)->*(ptrToMember))
 }  // namespace
 
 namespace offline_pages {
 
 RequestPicker::RequestPicker(RequestQueue* requestQueue,
                              OfflinerPolicy* policy,
-                             RequestNotifier* notifier)
+                             RequestNotifier* notifier,
+                             RequestCoordinatorEventLogger* event_logger)
     : queue_(requestQueue),
       policy_(policy),
       notifier_(notifier),
+      event_logger_(event_logger),
       fewer_retries_better_(false),
       earlier_requests_better_(false),
       weak_ptr_factory_(this) {}
 
 RequestPicker::~RequestPicker() {}
 
 // Entry point for the async operation to choose the next request.
 void RequestPicker::ChooseNextRequest(
     RequestCoordinator::RequestPickedCallback picked_callback,
     RequestCoordinator::RequestNotPickedCallback not_picked_callback,
@@ skipping 212 matching lines @@
     }
   }
 }
 
 // Callback used after expired requests are deleted from the queue and notifies
 // the coordinator.
 void RequestPicker::OnRequestExpired(
     const RequestQueue::UpdateMultipleRequestResults& results,
     const std::vector<std::unique_ptr<SavePageRequest>> requests) {
   std::vector<std::unique_ptr<SavePageRequest>>::const_iterator request;
-  for (request = requests.begin(); request != requests.end(); ++request)
+  for (request = requests.begin(); request != requests.end(); ++request) {
     notifier_->NotifyCompleted(
         *(request->get()),
         RequestCoordinator::BackgroundSavePageResult::EXPIRED);
+    event_logger_->RecordDroppedSavePageRequest(

[Dmitry Titov, 2016/09/12 19:43:13]

I'd record the log before calling NotifyCompleted, since NotifyCompleted just
synchronously calls into external observers and they can do anything. There is a
good reason to do that right before exiting the operation, since even 'this'
pointer is not guaranteed, strictly speaking.

[dougarnett, 2016/09/12 20:51:49]

Done.

+        request->get()->client_id().name_space,
+        RequestCoordinator::BackgroundSavePageResult::EXPIRED,
+        request->get()->request_id());
+  }
 }
 
 }  // namespace offline_pages