[Background Fetch] Cleanup/fix thread safety

content/browser/background_fetch/background_fetch_request_info.h

 // Copyright 2017 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 CONTENT_BROWSER_BACKGROUND_FETCH_REQUEST_INFO_H_
 #define CONTENT_BROWSER_BACKGROUND_FETCH_REQUEST_INFO_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
-#include "base/memory/ref_counted.h"
+#include "base/memory/ref_counted_delete_on_sequence.h"
+#include "base/sequence_checker.h"
 #include "base/time/time.h"
 #include "content/browser/background_fetch/background_fetch_constants.h"
 #include "content/common/content_export.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "content/public/browser/download_item.h"
 #include "url/gurl.h"
 
 namespace content {
 
 class DownloadItem;
 
 // Simple class to encapsulate the components of a fetch request.
 // TODO(peter): This can likely change to have a single owner, and thus become
 // an std::unique_ptr<>, when persistent storage has been implemented.
 class CONTENT_EXPORT BackgroundFetchRequestInfo
-    : public base::RefCountedThreadSafe<BackgroundFetchRequestInfo> {
+    : public base::RefCountedDeleteOnSequence<BackgroundFetchRequestInfo> {
  public:
   BackgroundFetchRequestInfo(int request_index,
                              const ServiceWorkerFetchRequest& fetch_request);
 
   // Populates the cached state for the in-progress |download_item|.
-  void PopulateDownloadState(DownloadItem* download_item,
-                             DownloadInterruptReason download_interrupt_reason);
+  void PopulateDownloadStateOnUI(
+      DownloadItem* download_item,
+      DownloadInterruptReason download_interrupt_reason);
+
+  void SetDownloadStatePopulated();
 
   // Populates the response portion of this object from the information made
   // available in the |download_item|.
-  void PopulateResponseFromDownloadItem(DownloadItem* download_item);
+  void PopulateResponseFromDownloadItemOnUI(DownloadItem* download_item);
+
+  void SetResponseDataPopulated();
 
   // Returns the index of this request within a Background Fetch registration.
   int request_index() const { return request_index_; }
 
   // Returns the Fetch API Request object that details the developer's request.
   const ServiceWorkerFetchRequest& fetch_request() const {
     return fetch_request_;
   }
 
   // Returns the response code for the download. Available for both successful
@@ skipping 14 matching lines @@
   // Returns the absolute path to the file in which the response is stored.
   const base::FilePath& GetFilePath() const;
 
   // Returns the size of the file containing the response, in bytes.
   int64_t GetFileSize() const;
 
   // Returns the time at which the response was completed.
   const base::Time& GetResponseTime() const;
 
  private:
-  friend class base::RefCountedThreadSafe<BackgroundFetchRequestInfo>;
+  friend class base::RefCountedDeleteOnSequence<BackgroundFetchRequestInfo>;
+  friend class base::DeleteHelper<BackgroundFetchRequestInfo>;
   friend class BackgroundFetchCrossOriginFilterTest;
 
   ~BackgroundFetchRequestInfo();
 
   // ---- Data associated with the request -------------------------------------
 
   int request_index_ = kInvalidBackgroundFetchRequestIndex;
   ServiceWorkerFetchRequest fetch_request_;
 
   // ---- Data associated with the in-progress download ------------------------
@@ skipping 11 matching lines @@
   // ---- Data associated with the response ------------------------------------
 
   // Indicates whether response data has been populated.
   bool response_data_populated_ = false;
 
   std::vector<GURL> url_chain_;
   base::FilePath file_path_;
   int64_t file_size_ = 0;
   base::Time response_time_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(BackgroundFetchRequestInfo);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BACKGROUND_FETCH_REQUEST_INFO_H_