[Offline pages] Rename REMOVED to USER_CANCELED and add better foot note descriptions for histogram…

components/offline_pages/core/background/request_coordinator.cc

Index: components/offline_pages/core/background/request_coordinator.cc
diff --git a/components/offline_pages/core/background/request_coordinator.cc b/components/offline_pages/core/background/request_coordinator.cc
index 78cbccf1ffb625e08f1e9716245789f687330f6b..2ec9fbe59f7b21ffbbb10aed7e9f496b44987cc1 100644
--- a/components/offline_pages/core/background/request_coordinator.cc
+++ b/components/offline_pages/core/background/request_coordinator.cc
@@ -414,7 +414,7 @@ void RequestCoordinator::RemoveRequests(
       request_ids,
       base::Bind(&RequestCoordinator::HandleRemovedRequestsAndCallback,
                  weak_ptr_factory_.GetWeakPtr(), callback,
-                 RequestNotifier::BackgroundSavePageResult::REMOVED));
+                 RequestNotifier::BackgroundSavePageResult::USER_CANCELED));
 
   // Record the network quality when this request is removed.
   if (network_quality_estimator_) {