arc: Support pinned apps across Arc-enabled and Arc-disabled platforms.

chrome/browser/ui/app_list/app_list_syncable_service.h

Index: chrome/browser/ui/app_list/app_list_syncable_service.h
diff --git a/chrome/browser/ui/app_list/app_list_syncable_service.h b/chrome/browser/ui/app_list/app_list_syncable_service.h
index 5b25ef88311263c26cf0068a893aec9ddfa50d82..f5c93b6eb3b932ab7c3fdee0fcdb43be5c3f7172 100644
--- a/chrome/browser/ui/app_list/app_list_syncable_service.h
+++ b/chrome/browser/ui/app_list/app_list_syncable_service.h
@@ -11,6 +11,7 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "base/observer_list.h"
 #include "build/build_config.h"
 #include "chrome/browser/apps/drive/drive_app_uninstall_sync_service.h"
 #include "chrome/browser/sync/glue/sync_start_util.h"
@@ -59,10 +60,22 @@ class AppListSyncableService : public syncer::SyncableService,
     std::string item_name;
     std::string parent_id;
     syncer::StringOrdinal item_ordinal;
+    syncer::StringOrdinal item_pin_ordinal;
 
     std::string ToString() const;
   };
 
+  class Observer {
+   public:
+    // Notifies that sync model was updated.
+    virtual void OnSyncModelUpdated() = 0;
+
+   protected:
+    virtual ~Observer() = default;
+  };
+
+  using SyncItemMap = std::map<std::string, SyncItem*>;
+
   // Populates the model when |extension_system| is ready.
   AppListSyncableService(Profile* profile,
                          extensions::ExtensionSystem* extension_system);
@@ -88,9 +101,23 @@ class AppListSyncableService : public syncer::SyncableService,
   // Sets the name of the folder for OEM apps.
   void SetOemFolderName(const std::string& name);
 
+  // Returns optional pin position for the app specified by |app_id|. If app is
+  // not synced or does not have associated pin position then empty ordinal is
+  // returned.
+  syncer::StringOrdinal GetPinPosition(const std::string& app_id);
+
+  // Sets pin position and how it is pinned for the app specified by |app_id|.
+  // Empty |item_pin_ordinal| indicates that the app has no pin.
+  void SetPinPosition(const std::string& app_id,
+                      const syncer::StringOrdinal& item_pin_ordinal);
+
   // Gets the app list model, building it if it doesn't yet exist.
   AppListModel* GetModel();
 
+  // Registers new observers and makes sure that service is started.
+  void AddObserverAndStart(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
   Profile* profile() { return profile_; }
   size_t GetNumSyncItemsForTest();
   const std::string& GetOemFolderNameForTest() const {
@@ -98,6 +125,8 @@ class AppListSyncableService : public syncer::SyncableService,
   }
   void ResetDriveAppProviderForTest();
 
+  const SyncItemMap& sync_items() const { return sync_items_; }
+
   // syncer::SyncableService
   syncer::SyncMergeResult MergeDataAndStartSyncing(
       syncer::ModelType type,
@@ -112,7 +141,6 @@ class AppListSyncableService : public syncer::SyncableService,
 
  private:
   class ModelObserver;
-  typedef std::map<std::string, SyncItem*> SyncItemMap;
 
   // KeyedService
   void Shutdown() override;
@@ -202,6 +230,9 @@ class AppListSyncableService : public syncer::SyncableService,
   // an OEM (extension->was_installed_by_oem() is true).
   bool AppIsOem(const std::string& id);
 
+  // Helper that notifies observers that sync model has been updated.
+  void NotifyObserversSyncUpdated();
+
   Profile* profile_;
   extensions::ExtensionSystem* extension_system_;
   std::unique_ptr<AppListModel> model_;
@@ -219,6 +250,9 @@ class AppListSyncableService : public syncer::SyncableService,
   bool first_app_list_sync_;
   std::string oem_folder_name_;
 
+  // List of observers.
+  base::ObserverList<Observer> observer_list_;
+
   // Provides integration with Drive apps.
   std::unique_ptr<DriveAppProvider> drive_app_provider_;