Add a NavigationThrottle to the public content/ interface

content/public/test/navigation_handle_tester.cc

Index: content/public/test/navigation_handle_tester.cc
diff --git a/content/public/test/navigation_handle_tester.cc b/content/public/test/navigation_handle_tester.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a2788e23eae46b69208900aa11db3534440630c7
--- /dev/null
+++ b/content/public/test/navigation_handle_tester.cc
@@ -0,0 +1,36 @@
+// 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/public/test/navigation_handle_tester.h"
+
+#include "content/browser/frame_host/navigator.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/public/browser/navigation_handle.h"
+#include "content/public/browser/web_contents.h"
+#include "content/test/test_navigation_handle.h"
+
+namespace content {
+
+// static
+NavigationHandleTester* NavigationHandleTester::For(
+    NavigationHandle* navigation_handle) {
+  return static_cast<TestNavigationHandle*>(navigation_handle);
+}
+
+// static
+NavigationHandle* NavigationHandleTester::CreateTestNavigationHandle(
+    const GURL& url,
+    const GURL& validated_url,
+    bool is_main_frame,
+    WebContents* web_contents) {
+  return TestNavigationHandle::Create(
+      url, validated_url, is_main_frame,
+      static_cast<WebContentsImpl*>(web_contents)
+          ->GetMainFrame()
+          ->frame_tree_node()
+          ->navigator()
+          ->GetDelegate());
+}
+
+}  // namespace content