[sync] Add typed url sync metadata to the history db

components/history/core/browser/history_database.h

 // Copyright (c) 2012 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 COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_
 #define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_
 
 #include <stddef.h>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "components/history/core/browser/download_database.h"
 #include "components/history/core/browser/history_types.h"
+#include "components/history/core/browser/typed_url_sync_metadata_database.h"
 #include "components/history/core/browser/url_database.h"
 #include "components/history/core/browser/visit_database.h"
 #include "components/history/core/browser/visitsegment_database.h"
 #include "sql/connection.h"
 #include "sql/init_status.h"
-#include "sql/meta_table.h"
 
 #if defined(OS_ANDROID)
 #include "components/history/core/browser/android/android_cache_database.h"
 #include "components/history/core/browser/android/android_urls_database.h"
 #endif
 
 namespace base {
 class FilePath;
 }
 
 class InMemoryURLIndexTest;
 
 namespace history {
 
 // Encapsulates the SQL connection for the history database. This class holds
 // the database connection and has methods the history system (including full
 // text search) uses for writing and retrieving information.
 //
 // We try to keep most logic out of the history database; this should be seen
 // as the storage interface. Logic for manipulating this storage layer should
 // be in HistoryBackend.cc.
 class HistoryDatabase : public DownloadDatabase,
 #if defined(OS_ANDROID)
                         public AndroidURLsDatabase,
                         public AndroidCacheDatabase,
 #endif
+                        public TypedURLSyncMetadataDatabase,
                         public URLDatabase,
                         public VisitDatabase,
                         public VisitSegmentDatabase {
  public:
   // A simple class for scoping a history database transaction. This does not
   // support rollback since the history database doesn't, either.
   class TransactionScoper {
    public:
     explicit TransactionScoper(HistoryDatabase* db) : db_(db) {
       db_->BeginTransaction();
@@ skipping 126 matching lines @@
 
 #if !defined(OS_WIN)
   // Converts the time epoch in the database from being 1970-based to being
   // 1601-based which corresponds to the change in Time.internal_value_.
   void MigrateTimeEpoch();
 #endif
 
   // ---------------------------------------------------------------------------
 
   sql::Connection db_;
-  sql::MetaTable meta_table_;

[brettw, 2017/03/20 17:27:06]

Conceptually, the meta table should live at this layer since it's really a
global history database thing.

The not-so-great inheritance use by the history system is my fault from long ago
that makes this more difficult than it might otherwise be.

The best thing I can think of is if your typed table class had a
set_meta_table(MetaTable* table) member. HistoryDatabase would set this on init
and clear this in it's destructor (to prevent dangling pointers on destruction).
What do you think?

[Gang Wu, 2017/03/20 21:34:47]

I copied idea from db_ and GetDB(), in base class has a virtual class to get
MetaTable, do you think it is ok?

 
   base::Time cached_early_expiration_threshold_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryDatabase);
 };
 
 }  // namespace history
 
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_DATABASE_H_