Refactor net predictor to use ResourceThrottles

chrome/browser/renderer_host/predictor_resource_throttle.h

+// 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 CHROME_BROWSER_RENDERER_HOST_PREDICTOR_RESOURCE_THROTTLE_H_
+#define CHROME_BROWSER_RENDERER_HOST_PREDICTOR_RESOURCE_THROTTLE_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "content/public/browser/resource_throttle.h"
+
+namespace chrome_browser_net {
+class Predictor;
+}
+
+namespace net {
+struct RedirectInfo;
+class URLRequest;
+}
+
+class ProfileIOData;
+
+// This resource throttle tracks requests in order to help the predictor learn
+// resource relationships. It notifies the predictor of redirect and referrer
+// relationships, and populates the predictor's timed cache of ongoing
+// navigations. It also initiates predictive actions based on subframe
+// requests and redirects.
+// Note: This class does not issue predictive actions off of the initial main
+// frame request (before any redirects). That is done on the UI thread in
+// response to navigation callbacks in predictor_tab_helper.cc.
+// TODO(csharrison): This class shouldn't depend on chrome_browser_net. The
+// predictor should probably be moved here (along with its dependencies).
+// TODO(csharrison): When the PreconnectMore experiment is over, move all
+// prediction dispatching to the tab helper.
+class PredictorResourceThrottle : public content::ResourceThrottle {
+ public:
+  PredictorResourceThrottle(net::URLRequest* request,
+                            chrome_browser_net::Predictor* predictor);
+  ~PredictorResourceThrottle() override;
+
+  static std::unique_ptr<PredictorResourceThrottle> MaybeCreate(
+      net::URLRequest* request,
+      ProfileIOData* io_data);
+
+  // content::ResourceThrottle:
+  void WillStartRequest(bool* defer) override;
+  void WillRedirectRequest(const net::RedirectInfo& redirect_info,
+                           bool* defer) override;
+  const char* GetNameForLogging() const override;
+
+ private:
+  net::URLRequest* request_;
+  chrome_browser_net::Predictor* predictor_;
+
+  DISALLOW_COPY_AND_ASSIGN(PredictorResourceThrottle);
+};
+
+#endif  // CHROME_BROWSER_RENDERER_HOST_PREDICTOR_RESOURCE_THROTTLE_H_