Add a way to send the resource percentage signal to the RC.

chrome/browser/android/offline_pages/background_loader_offliner.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 "chrome/browser/android/offline_pages/background_loader_offliner.h"
 
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/sys_info.h"
@@ skipping 220 matching lines @@
       if (save_state_ == NONE) {
         did_snapshot_on_last_retry_ = true;
         StartSnapshot();
       }
       return true;
     }
   }
   return false;
 }
 
+void BackgroundLoaderOffliner::ObserveResourceTracking(
+    const ResourceDataType type,
+    int64_t started_count,
+    int64_t completed_count) {
+  // Add the signal to extra data, and use for tracking.
+  if (type == ResourceDataType::IMAGE)
+    AddResourceSignal(type, started_count, completed_count);
+}
+
 void BackgroundLoaderOffliner::MarkLoadStartTime() {
   load_start_time_ = base::TimeTicks::Now();
 }
 
 void BackgroundLoaderOffliner::DocumentAvailableInMainFrame() {
   snapshot_controller_->DocumentAvailableInMainFrame();
   is_low_bar_met_ = true;
 
   // Add this signal to signal_data_.
   AddLoadingSignal("DocumentAvailableInMainFrame");
@@ skipping 235 matching lines @@
   base::TimeTicks current_time = base::TimeTicks::Now();
   base::TimeDelta delay_so_far = current_time - load_start_time_;
   // We would prefer to use int64_t here, but JSON does not support that type.
   // Given the choice between int and double, we choose to implicitly convert to
   // a double since it maintains more precision (we can get a longer time in
   // milliseconds than we can with a 2 bit int, 53 bits vs 32).
   double delay = delay_so_far.InMilliseconds();
   signal_data_.SetDouble(signal_name, delay);
 }
 
+void BackgroundLoaderOffliner::AddResourceSignal(const ResourceDataType type,
+                                                 int64_t started_count,
+                                                 int64_t completed_count) {
+  double percentage = 100.0 * static_cast<double>(completed_count) /
+                      static_cast<double>(started_count);
+  // TODO(petewil): Use actual signal type instead of hardcoding name to image.
+  signal_data_.SetDouble("ImagePercentage", percentage);
+  signal_data_.SetDouble("StartedImages", started_count);
+  signal_data_.SetDouble("CompletedImages", completed_count);
+}
+
 }  // namespace offline_pages
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(offline_pages::OfflinerData);