sync: Add GetAllSyncData to sync/api

chrome/browser/history/history_unittest.cc

Index: chrome/browser/history/history_unittest.cc
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index 28db9ba33ad32311857da63589dc552fcf46ef1f..c41596f8d676e37951494477a3deb0e2b9fbf4ab 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -1554,6 +1554,10 @@ class TestChangeProcessor : public syncer::SyncChangeProcessor {
     return syncer::SyncError();
   }
 
+  virtual syncer::SyncDataList GetAllSyncData(syncer::ModelType type) const {
+    return syncer::SyncDataList();
+  }
+
   const syncer::SyncChangeList& GetChanges() const {
     return changes_;
   }
@@ -1585,6 +1589,10 @@ class SyncChangeProcessorDelegate : public syncer::SyncChangeProcessor {
     return recipient_->ProcessSyncChanges(from_here, change_list);
   }
 
+  virtual syncer::SyncDataList GetAllSyncData(syncer::ModelType type) const {
+    return recipient_->GetAllSyncData(type);
+  }
+
  private:
   // The recipient of all sync changes.
   syncer::SyncChangeProcessor* const recipient_;