Refactor the offline page storage to include client namespace and id.

components/offline_pages/offline_page_metadata_store_impl.h

Index: components/offline_pages/offline_page_metadata_store_impl.h
diff --git a/components/offline_pages/offline_page_metadata_store_impl.h b/components/offline_pages/offline_page_metadata_store_impl.h
index f9248c65e26bdc2b80644f5117ce2edf47034187..cea458b10b5e9e455fa203684c9a79b7e39eee3c 100644
--- a/components/offline_pages/offline_page_metadata_store_impl.h
+++ b/components/offline_pages/offline_page_metadata_store_impl.h
@@ -25,7 +25,7 @@ namespace offline_pages {
 
 class OfflinePageEntry;
 
-// Implements OfflinePageMetadataStore using leveldb_proto::Protoatabase
+// Implements OfflinePageMetadataStore using leveldb_proto::ProtoDatabase
 // component. Stores metadata of offline pages as serialized protobufs in a
 // LevelDB key/value pairs.
 // Underlying implementation guarantees that all of the method calls will be
@@ -42,7 +42,7 @@ class OfflinePageMetadataStoreImpl : public OfflinePageMetadataStore {
   void Load(const LoadCallback& callback) override;
   void AddOrUpdateOfflinePage(const OfflinePageItem& offline_page_record,
                               const UpdateCallback& callback) override;
-  void RemoveOfflinePages(const std::vector<int64_t>& bookmark_ids,
+  void RemoveOfflinePages(const std::vector<int64_t>& offline_ids,
                           const UpdateCallback& callback) override;
   void Reset(const ResetCallback& callback) override;
 
@@ -67,6 +67,14 @@ class OfflinePageMetadataStoreImpl : public OfflinePageMetadataStore {
 
   void ResetDone(const ResetCallback& callback, bool success);
 
+  // Called when a database has to be migrated from old bookmark ids
+  // to new offline ids.
+  // TODO: Remove this eventually.

[fgorski, 2016/02/26 19:29:22]

TODO(bburns): ?
Also this is part of an upgrade path, I don't know if we want to remove it ever.

[bburns, 2016/02/27 00:48:19]

Done.  Softened the comment.  Seems like its cruft we'll want to remove in
_sometime_ (e.g. maybe years...)

+  void DatabaseUpdateDone(const OfflinePageMetadataStore::LoadCallback& cb,
+                          LoadStatus status,
+                          const std::vector<OfflinePageItem>& result,
+                          bool success);
+
   scoped_refptr<base::SequencedTaskRunner> background_task_runner_;
   base::FilePath database_dir_;
   scoped_ptr<leveldb_proto::ProtoDatabase<OfflinePageEntry>> database_;