Add Store+Sync to reading list.

ios/chrome/browser/reading_list/reading_list_entry.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 IOS_CHROME_BROWSER_READING_LIST_READING_LIST_ENTRY_H_
 #define IOS_CHROME_BROWSER_READING_LIST_READING_LIST_ENTRY_H_
 
 #include <string>
+#include <vector>
 
 #include "base/macros.h"
+#include "base/time/default_tick_clock.h"
+#include "base/time/time.h"
 #include "net/base/backoff_entry.h"
 #include "url/gurl.h"
 
+namespace reading_list {
+class ReadingListLocal;
+}
+
+namespace sync_pb {
+class ReadingListSpecifics;
+}
+
 // An entry in the reading list. The URL is a unique identifier for an entry, as
 // such it should not be empty and is the only thing considered when comparing
 // entries.
 class ReadingListEntry {
  public:
   ReadingListEntry(const GURL& url, const std::string& title);
   ReadingListEntry(const GURL& url,
                    const std::string& title,
                    std::unique_ptr<net::BackoffEntry> backoff);
   ReadingListEntry(ReadingListEntry&& entry);
@@ skipping 17 matching lines @@
   // be called if the state is "PROCESSED".
   const GURL& DistilledURL() const;
   // The time before the next try. This is automatically increased when the
   // state is set to WILL_RETRY or ERROR from a non-error state.
   base::TimeDelta TimeUntilNextTry() const;
   // The number of time chrome failed to download this entry. This is
   // automatically increased when the state is set to WILL_RETRY or ERROR from a
   // non-error state.
   int FailedDownloadCounter() const;
 
+  // The last update time of the entry. This value may be used to sort the
+  // entries. The value is in microseconds since Jan 1st 1970.
+  int64_t UpdateTime() const;
+
+  // Set the update time to now.
+  void MarkEntryUpdated();
+
+  // Returns a protobuf encoding the content of this ReadingListEntry.
+  std::unique_ptr<reading_list::ReadingListLocal> AsReadingListLocal(

[jif, 2016/11/07 12:30:51]

|AsReadingListSpecifics| is "for sync."
what is |AsReadingListLocal| for?

[Olivier, 2016/11/07 18:18:45]

for local storage. Added to comment.

+      bool read) const;
+
+  // Returns a protobuf encoding the content of this ReadingListEntry for sync.
+  std::unique_ptr<sync_pb::ReadingListSpecifics> AsReadingListSpecifics(
+      bool read) const;
+
+  // Created a ReadingListEntry from the protobuf format.
+  static std::unique_ptr<ReadingListEntry> FromReadingListLocal(
+      const reading_list::ReadingListLocal& pb_entry);
+
+  // Created a ReadingListEntry from the protobuf format.
+  static std::unique_ptr<ReadingListEntry> FromReadingListSpecifics(
+      const sync_pb::ReadingListSpecifics& pb_entry);
+
+  // Merge the local data from |other| to this.
+  // |other| must not be used after this point.
+  void MergeLocalStateFrom(ReadingListEntry& other);

[jif, 2016/11/07 12:30:51]

with "ReadingListEntry&&" you wouldn't have to write "|other| must not be used
after this point.", and it would be obvious to the caller not to reuse the
parameter because they will have had to std::move it.

[Olivier, 2016/11/07 18:18:45]

This is more complicated than  that :)

+
   ReadingListEntry& operator=(ReadingListEntry&& other);
+
   bool operator==(const ReadingListEntry& other) const;
 
+  // Returns whether |lhs| is more recent than |rhs|.
+  static bool CompareEntryUpdateTime(const ReadingListEntry& lhs,
+                                     const ReadingListEntry& rhs);
+
   // Sets the title.
   void SetTitle(const std::string& title);
   // Sets the distilled URL and switch the state to PROCESSED and reset the time
   // until the next try.
   void SetDistilledURL(const GURL& url);
   // Sets the state to one of PROCESSING, WILL_RETRY or ERROR.
   void SetDistilledState(DistillationState distilled_state);
 
  private:
+  ReadingListEntry(const GURL& url,
+                   const std::string& title,
+                   int64_t creation_time,
+                   int64_t update_time,
+                   DistillationState distilled_state,
+                   const GURL& distilled_url,
+                   int failed_download_counter,
+                   std::unique_ptr<net::BackoffEntry> backoff);
   GURL url_;
   std::string title_;
   GURL distilled_url_;
   DistillationState distilled_state_;
+
   std::unique_ptr<net::BackoffEntry> backoff_;
   int failed_download_counter_;
 
+  // These value are in microseconds since Jan 1st 1970. They are used for
+  // sorting the entries from the database. They are kept in int64_t to avoid
+  // conversion on each save/read event.
+  int64_t creation_time_us_;
+  int64_t update_time_us_;
+
   DISALLOW_COPY_AND_ASSIGN(ReadingListEntry);
 };
 
 #endif  // IOS_CHROME_BROWSER_READING_LIST_READING_LIST_ENTRY_H_