Add a Dns preresolve interface in //content

content/browser/loader/resource_hints_controller.h

Index: content/browser/loader/resource_hints_controller.h
diff --git a/content/browser/loader/resource_hints_controller.h b/content/browser/loader/resource_hints_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..60b2314d0fab5ccaa4da45b69a422535b909b58a
--- /dev/null
+++ b/content/browser/loader/resource_hints_controller.h
@@ -0,0 +1,38 @@
+// Copyright 2016 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_RESOURCE_HINTS_CONTROLLER_H_
+#define CONTENT_BROWSER_LOADER_RESOURCE_HINTS_CONTROLLER_H_
+
+#include "base/macros.h"
+#include "net/base/completion_callback.h"
+#include "url/gurl.h"
+
+namespace content {
+
+class ResourceContext;
+
+// Scoped to the ResourceDispatcherHostImpl. This class manages DNS
+// preresolutions. Once resource hints go through mojo it will also respond to
+// mojo requests from Blink to preconnect / preresolve.
+class ResourceHintsController {
+ public:
+  ResourceHintsController();
+  ~ResourceHintsController();
+  int PreresolveUrl(content::ResourceContext* resource_context,
+                    const GURL& url,
+                    const net::CompletionCallback& callback);
+
+ private:
+  struct DnsRequest;
+  void OnResolveComplete(std::unique_ptr<DnsRequest> request,
+                         const net::CompletionCallback& callback,
+                         int result);
+
+  DISALLOW_COPY_AND_ASSIGN(ResourceHintsController);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_RESOURCE_HINTS_CONTROLLER_H_