Extension syncing: Introduce a NeedsSync pref

chrome/browser/extensions/sync_bundle.h

Index: chrome/browser/extensions/sync_bundle.h
diff --git a/chrome/browser/extensions/sync_bundle.h b/chrome/browser/extensions/sync_bundle.h
index 750933f5b9163b8cbe43791b6b8946d3446f69b6..adebbb10754c9d2acf462ceb29ec593c23d6498c 100644
--- a/chrome/browser/extensions/sync_bundle.h
+++ b/chrome/browser/extensions/sync_bundle.h
@@ -17,34 +17,23 @@ class ExtensionSyncService;
 
 namespace extensions {
 
-class Extension;
 class ExtensionSyncData;
 
 class SyncBundle {
  public:
-  explicit SyncBundle(ExtensionSyncService* sync_service);
+  SyncBundle();
   ~SyncBundle();
 
-  void MergeDataAndStartSyncing(
-      const syncer::SyncDataList& initial_sync_data,
-      scoped_ptr<syncer::SyncChangeProcessor> sync_processor);
+  void StartSyncing(scoped_ptr<syncer::SyncChangeProcessor> sync_processor);
 
   // Resets this class back to its default values, which will disable all
   // syncing until StartSyncing is called again.
   void Reset();
 
   // Has this bundle started syncing yet?
-  // Returns true if MergeDataAndStartSyncing has been called, false otherwise.
+  // Returns true if StartSyncing has been called, false otherwise.
   bool IsSyncing() const;
 
-  // Checks if the extension with the given |id| is synced.
-  bool HasExtensionId(const std::string& id) const;
-
-  // Whether the given extension should be included in the SyncDataList to be
-  // sent to the server. Returns false if there is pending data that should be
-  // used instead.
-  bool ShouldIncludeInLocalSyncDataList(const Extension& extension) const;
-
   // Handles the given list of local SyncDatas. This updates the set of synced
   // extensions as appropriate, and then pushes the corresponding SyncChanges
   // to the server.
@@ -57,12 +46,15 @@ class SyncBundle {
                         const syncer::SyncData& sync_data);
 
   // Pushes any sync changes to |extension| to the server.
-  void PushSyncAddOrUpdate(const Extension& extension);
+  void PushSyncAddOrUpdate(const std::string& extension_id,
+                           const syncer::SyncData& sync_data);
 
-  // Applies the given SyncChange coming from the server.
-  void ApplySyncChange(const syncer::SyncChange& sync_change);
+  // Applies the given sync change coming in from the server. This just updates
+  // the list of synced extensions.
+  void ApplySyncData(const ExtensionSyncData& extension_sync_data);
 
-  // Checks if the extension with the given |id| is pending to be synced.
+  // Checks if there is pending sync data for the extension with the given |id|
+  // that should be sent to the server instead of the local state.
   bool HasPendingExtensionId(const std::string& id) const;
 
   // Adds a pending extension to be synced.
@@ -82,16 +74,18 @@ class SyncBundle {
 
   void AddSyncedExtension(const std::string& id);
   void RemoveSyncedExtension(const std::string& id);
-
-  // Changes an extension from being pending to synced.
-  void MarkPendingExtensionSynced(const std::string& id);
-
-  ExtensionSyncService* sync_service_;  // Owns us.
+  bool HasSyncedExtension(const std::string& id) const;
 
   scoped_ptr<syncer::SyncChangeProcessor> sync_processor_;
 
+  // Stores the set of extensions we know about. Used to decide if a sync change
+  // should be ACTION_ADD or ACTION_UPDATE.
   std::set<std::string> synced_extensions_;
 
+  // This stores changes we got from sync that we couldn't apply immediately
+  // (such as installing a new extension, or an update). We'll send this back
+  // to the server instead of the local state, to prevent the sync state from
+  // flipping back and forth until all clients are on the same state.
   std::map<std::string, ExtensionSyncData> pending_sync_data_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBundle);