Add a NavigationThrottle to the public content/ interface

content/browser/loader/navigation_resource_throttle.h

Index: content/browser/loader/navigation_resource_throttle.h
diff --git a/content/browser/loader/navigation_resource_throttle.h b/content/browser/loader/navigation_resource_throttle.h
new file mode 100644
index 0000000000000000000000000000000000000000..e46b59d06694d755b3273273544583374d23a94b
--- /dev/null
+++ b/content/browser/loader/navigation_resource_throttle.h
@@ -0,0 +1,44 @@
+// 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.
+
+#ifndef CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_
+#define CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_
+
+#include "base/basictypes.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/navigation_throttle.h"
+#include "content/public/browser/resource_throttle.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace content {
+
+// This ResourceThrottle is used to convey throttling information to the UI
+// thread during navigations. The UI thread can then use its NavigationThrottle
+// mechanism to interact with the navigation.
+class NavigationResourceThrottle : public ResourceThrottle {
+ public:
+  NavigationResourceThrottle(net::URLRequest* request);
+  ~NavigationResourceThrottle() override;
+
+  // ResourceThrottle overrides:
+  void WillStartRequest(bool* defer) override;
+  void WillRedirectRequest(const net::RedirectInfo& redirect_info,
+                           bool* defer) override;
+  const char* GetNameForLogging() const override;
+
+ private:
+  void OnUIChecksPerformed(NavigationThrottle::ThrottleCheckResult result);
+
+  net::URLRequest* request_;
+  base::WeakPtrFactory<NavigationResourceThrottle> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(NavigationResourceThrottle);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_NAVIGATION_RESOURCE_THROTTLE_H_