Record the tab state during data use

chrome/browser/data_use_measurement/chrome_data_use_ascriber.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 CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_H_
 #define CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_H_
 
 #include <list>
 #include <memory>
 #include <string>
@@ skipping 39 matching lines @@
 // navigation information on the IO thread.
 class ChromeDataUseAscriber : public DataUseAscriber {
  public:
   ChromeDataUseAscriber();
 
   ~ChromeDataUseAscriber() override;
 
   // DataUseAscriber implementation:
   ChromeDataUseRecorder* GetDataUseRecorder(net::URLRequest* request,
                                             bool can_create_new) override;
+  const DataUseRecorder* GetDataUseRecorderIfExists(
+      const net::URLRequest* request) const override;
   void OnUrlRequestDestroyed(net::URLRequest* request) override;
   std::unique_ptr<URLRequestClassifier> CreateURLRequestClassifier()
       const override;
 
   // Called when a render frame host is created. When the render frame is a main
   // frame, |main_render_process_id| and |main_render_frame_id| should be -1.
   void RenderFrameCreated(int render_process_id,
                           int render_frame_id,
                           int main_render_process_id,
                           int main_render_frame_id);
@@ skipping 98 matching lines @@
 
   // Contains the mainframe IDs that are currently visible.
   base::hash_set<RenderFrameHostID> visible_main_render_frames_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeDataUseAscriber);
 };
 
 }  // namespace data_use_measurement
 
 #endif  // CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_H_