Network service: move URLLoaderThrottle and ThrottlingURLLoader.

content/public/child/url_loader_throttle.h

-// Copyright 2017 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_PUBLIC_RENDERER_URL_LOADER_THROTTLE_H_
-#define CONTENT_PUBLIC_RENDERER_URL_LOADER_THROTTLE_H_
-
-#include "content/common/content_export.h"
-#include "content/public/common/resource_type.h"
-
-class GURL;
-
-namespace net {
-struct RedirectInfo;
-}
-
-namespace content {
-
-// A URLLoaderThrottle gets notified at various points during the process of
-// loading a resource. At each stage, it has the opportunity to defer the
-// resource load.
-class CONTENT_EXPORT URLLoaderThrottle {
- public:
-  // An interface for the throttle implementation to resume (when deferred) or
-  // cancel the resource load.
-  class CONTENT_EXPORT Delegate {
-   public:
-    // Cancels the resource load with the specified error code.
-    virtual void CancelWithError(int error_code) = 0;
-
-    // Resumes the deferred resource load. It is a no-op if the resource load is
-    // not deferred or has already been canceled.
-    virtual void Resume() = 0;
-
-   protected:
-    virtual ~Delegate() {}
-  };
-
-  virtual ~URLLoaderThrottle() {}
-
-  // Called before the resource request is started.
-  virtual void WillStartRequest(const GURL& url,
-                                int load_flags,
-                                ResourceType resource_type,
-                                bool* defer) {}
-
-  // Called when the request was redirected.  |redirect_info| contains the
-  // redirect responses's HTTP status code and some information about the new
-  // request that will be sent if the redirect is followed, including the new
-  // URL and new method.
-  virtual void WillRedirectRequest(const net::RedirectInfo& redirect_info,
-                                   bool* defer) {}
-
-  // Called when the response headers and meta data are available.
-  virtual void WillProcessResponse(bool* defer) {}
-
-  void set_delegate(Delegate* delegate) { delegate_ = delegate; }
-
- protected:
-  URLLoaderThrottle() = default;
-
-  Delegate* delegate_ = nullptr;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_PUBLIC_RENDERER_URL_LOADER_THROTTLE_H_