sync: Expose sync functionality as functions

sync/engine/download.h

Index: sync/engine/download.h
diff --git a/sync/engine/download.h b/sync/engine/download.h
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+++ b/sync/engine/download.h
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+// Copyright (c) 2013 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 SYNC_ENGINE_DOWNLOAD_H_
+#define SYNC_ENGINE_DOWNLOAD_H_
+
+#include "sync/base/sync_export.h"
+#include "sync/internal_api/public/base/model_type.h"
+#include "sync/internal_api/public/util/syncer_error.h"
+
+namespace sync_pb {
+class DebugInfo;
+}  // namespace sync_pb
+
+namespace syncer {
+
+namespace sessions {
+class NudgeTracker;
+class SyncSession;
+struct SyncSourceInfo;
+}  // namespace sessions
+
+class Syncer;
+
+// This function executes a single GetUpdate request and stores the response in
+// the session's StatusController.  It constructs the type of request used to
+// keep types in sync when in normal mode.
+SYNC_EXPORT_PRIVATE SyncerError NormalDownloadUpdates(
+    sessions::SyncSession* session,
+    bool create_mobile_bookmarks_folder,
+    ModelTypeSet request_types,
+    const sessions::NudgeTracker& nudge_tracker);
+
+// This function executes a single GetUpdate request and stores the response in
+// the session's StatusController.  It constructs the type of request used to
+// initialize a type for the first time.
+SYNC_EXPORT_PRIVATE SyncerError DownloadUpdatesForConfigure(
+    sessions::SyncSession* session,
+    bool create_mobile_bookmarks_folder,
+    const syncer::sessions::SyncSourceInfo& source,
+    ModelTypeSet request_types);
+
+// This function executes a single GetUpdate request and stores the response in
+// the session's status controller.  It constructs the type of request used for
+// periodic polling.
+SYNC_EXPORT_PRIVATE SyncerError DownloadUpdatesForPoll(
+    sessions::SyncSession* session,
+    bool create_mobile_bookmarks_folder,
+    ModelTypeSet request_types);
+
+// A helper to set debug info.  Exposed only for testing.
+SYNC_EXPORT_PRIVATE void AppendClientDebugInfoIfNeeded(
+    sessions::SyncSession* session,
+    sync_pb::DebugInfo* debug_info);
+
+}  // namespace syncer
+
+#endif  // SYNC_ENGINE_DOWNLOAD_H_