[Offline Pages] Adds UMA for result of attempts to immediately start background loading.

components/offline_pages/background/request_coordinator.h

 // 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.
 
 #ifndef COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_
 
 #include <memory>
 
 #include "base/callback.h"
@@ skipping 151 matching lines @@
   // the next StartProcessing() call.
   bool is_canceled() {
     return is_stopped_;
   }
 
   OfflineEventLogger* GetLogger() {
     return &event_logger_;
   }
 
  private:
+  // Immediate start attempt status code for UMA.
+  // For any changes, also update corresponding histogram in histograms.xml.
+  enum OfflinerImmediateStartStatus {
+    // Did start processing request.
+    STARTED = 0,
+    // Already busy processing a request.
+    BUSY = 1,
+    // The Offliner did not accept processing the request.
+    NOT_ACCEPTED = 2,
+    // No current network connection.
+    NO_CONNECTION = 3,
+    // Weak network connection (worse than 2G speed)
+    // according to network quality estimator.
+    WEAK_CONNECTION = 4,
+    // Did not start because this is svelte device.
+    NOT_STARTED_ON_SVELTE = 5,
+    // NOTE: insert new values above this line and update histogram enum too.
+    STATUS_COUNT = 6,
+  };
+
   // Receives the results of a get from the request queue, and turns that into
   // SavePageRequest objects for the caller of GetQueuedRequests.
   void GetQueuedRequestsCallback(
       const GetRequestsCallback& callback,
       RequestQueue::GetRequestsResult result,
       std::vector<std::unique_ptr<SavePageRequest>> requests);
 
   // Receives the results of a get from the request queue, and turns that into
   // SavePageRequest objects for the caller of GetQueuedRequests.
   void GetRequestsForSchedulingCallback(
@@ skipping 16 matching lines @@
       BackgroundSavePageResult status,
       std::unique_ptr<UpdateRequestsResult> result);
 
   void HandleRemovedRequests(BackgroundSavePageResult status,
                              std::unique_ptr<UpdateRequestsResult> result);
 
   // Start processing now if connected (but with conservative assumption
   // as to other device conditions).
   void StartProcessingIfConnected();
 
+  OfflinerImmediateStartStatus TryImmediateStart();
+
   // Check the request queue, and schedule a task corresponding
   // to the least restrictive type of request in the queue.
   void ScheduleAsNeeded();
 
   // Callback from the request picker when it has chosen our next request.
   void RequestPicked(const SavePageRequest& request);
 
   // Callback from the request picker when no more requests are in the queue.
   // The parameter is a signal for what (if any) conditions to schedule future
   // processing for.
@@ skipping 101 matching lines @@
   base::TimeDelta offliner_timeout_;
   // Allows us to pass a weak pointer to callbacks.
   base::WeakPtrFactory<RequestCoordinator> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RequestCoordinator);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_