Add a NavigationThrottle to the public content/ interface

content/test/test_navigation_handle_factory.cc

Index: content/test/test_navigation_handle_factory.cc
diff --git a/content/test/test_navigation_handle_factory.cc b/content/test/test_navigation_handle_factory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..273525897d4ea0b59791f7f9f2b012c7384d6ae3
--- /dev/null
+++ b/content/test/test_navigation_handle_factory.cc
@@ -0,0 +1,27 @@
+// Copyright 2015 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/test/test_navigation_handle_factory.h"
+
+#include "content/test/test_navigation_handle.h"
+
+namespace content {
+
+TestNavigationHandleFactory::TestNavigationHandleFactory() {
+  NavigationHandleFactory::SetFactoryForTesting(this);
+}
+
+TestNavigationHandleFactory::~TestNavigationHandleFactory() {
+  NavigationHandleFactory::SetFactoryForTesting(nullptr);
+}
+
+scoped_ptr<NavigationHandleImpl> TestNavigationHandleFactory::CreateHandle(
+    const GURL& url,
+    bool is_main_frame,
+    NavigatorDelegate* delegate) {
+  return scoped_ptr<NavigationHandleImpl>(
+      TestNavigationHandle::Create(url, is_main_frame, delegate));
+}
+
+}  // namespace content