Fix history importing by delaying DownloadManager creation.

content/browser/download/download_id_factory.cc

Index: content/browser/download/download_id_factory.cc
diff --git a/content/browser/download/download_id_factory.cc b/content/browser/download/download_id_factory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6b0797f88c4a9f559c60b96f147082cca8a48ef1
--- /dev/null
+++ b/content/browser/download/download_id_factory.cc
@@ -0,0 +1,17 @@
+// Copyright (c) 2011 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.
+
+#include "content/browser/download/download_id_factory.h"
+
+#include "content/browser/download/download_id.h"
+
+DownloadIdFactory::DownloadIdFactory(DownloadId::Domain domain)
+  : domain_(domain),
+    next_id_(0) {
+}
+
+DownloadId DownloadIdFactory::GetNextId() {
+  base::AutoLock lock(lock_);
+  return DownloadId(domain_, next_id_++);
+}