PlzNavigate: Add first version of NavigationURLLoader.

content/browser/loader/navigation_url_loader_delegate.h

+// Copyright 2014 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_URL_LOADER_DELEGATE_H_
+#define CONTENT_BROWSER_LOADER_NAVIGATION_URL_LOADER_DELEGATE_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/common/content_export.h"
+
+namespace net {
+struct RedirectInfo;
+}
+
+namespace content {
+
+class StreamHandle;
+struct ResourceResponse;
+
+// PlzNavigate: The delegate interface to NavigationURLLoader.
+class CONTENT_EXPORT NavigationURLLoaderDelegate {
+ public:
+  // Called when the request is redirected. Call FollowRedirect to continue
+  // processing the request.
+  virtual void OnRequestRedirected(
+      const net::RedirectInfo& redirect_info,
+      const scoped_refptr<ResourceResponse>& response) = 0;
+
+  // Called when the request receives its response. No further calls will be
+  // made to the delegate. The response body is returned as a stream in
+  // |body_stream|.
+  virtual void OnResponseStarted(
+      const scoped_refptr<ResourceResponse>& response,
+      scoped_ptr<StreamHandle> body_stream) = 0;
+
+  // Called if the request fails before receving a response. |net_error| is a
+  // network error code for the failure.
+  virtual void OnRequestFailed(int net_error) = 0;
+
+ protected:
+  NavigationURLLoaderDelegate() {}
+  virtual ~NavigationURLLoaderDelegate() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NavigationURLLoaderDelegate);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_NAVIGATION_URL_LOADER_DELEGATE_H_