sync: Re-implement getAllNodes WebUI function

chrome/browser/sync/glue/sync_backend_host_core.h

Index: chrome/browser/sync/glue/sync_backend_host_core.h
diff --git a/chrome/browser/sync/glue/sync_backend_host_core.h b/chrome/browser/sync/glue/sync_backend_host_core.h
index 0c521002010b9efba573a30a34c670abf329946a..eb267a6223fa62d18627e2f1dc670940f6d00bd2 100644
--- a/chrome/browser/sync/glue/sync_backend_host_core.h
+++ b/chrome/browser/sync/glue/sync_backend_host_core.h
@@ -223,6 +223,12 @@ class SyncBackendHostCore
     return &release_request_context_signal_;
   }
 
+  void GetAllNodesForTypes(
+      syncer::ModelTypeSet types,
+      scoped_refptr<base::SequencedTaskRunner> task_runner,
+      base::Callback<void(const std::vector<syncer::ModelType>& type,
+                          ScopedVector<base::ListValue>) > callback);
+
  private:
   friend class base::RefCountedThreadSafe<SyncBackendHostCore>;
   friend class SyncBackendHostForProfileSyncTest;