Create LoadingDataCollector class and have observers rely on it instead of ResourcePrefetchPredictor

chrome/browser/predictors/loading_data_collector.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 CHROME_BROWSER_PREDICTORS_LOADING_DATA_COLLECTOR_H_
+#define CHROME_BROWSER_PREDICTORS_LOADING_DATA_COLLECTOR_H_
+
+#include "chrome/browser/predictors/resource_prefetch_predictor.h"
+#include "content/public/common/resource_type.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace predictors {
+
+// Records navigation events as reported by various observers to the database
+// and stats collection classes. All the non-static methods of this class need
+// to be called on the UI thread.
+class LoadingDataCollector
+    : public base::SupportsWeakPtr<LoadingDataCollector> {
+ public:
+  explicit LoadingDataCollector(
+      predictors::ResourcePrefetchPredictor* predictor);
+  ~LoadingDataCollector();
+
+  // Thread safe.
+  static bool ShouldRecordRequest(net::URLRequest* request,
+                                  content::ResourceType resource_type);
+  static bool ShouldRecordResponse(net::URLRequest* response);
+  static bool ShouldRecordRedirect(net::URLRequest* response);
+
+  // 'LoadingPredictorObserver' calls the below functions to inform the

[Benoit L, 2017/06/02 12:43:59]

and LoadingPredictorTabHelper, right?

[trevordixon, 2017/06/06 13:08:03]

Done.

+  // predictor of main frame and resource requests. Should only be called if the
+  // corresponding Should* functions return true.
+  void RecordURLRequest(
+      const predictors::ResourcePrefetchPredictor::URLRequestSummary& request);
+  void RecordURLResponse(
+      const predictors::ResourcePrefetchPredictor::URLRequestSummary& response);
+  void RecordURLRedirect(
+      const predictors::ResourcePrefetchPredictor::URLRequestSummary& response);
+
+  // Called when the main frame of a page completes loading.
+  void RecordMainFrameLoadComplete(const NavigationID& navigation_id);
+
+  // Called after the main frame's first contentful paint.
+  void RecordFirstContentfulPaint(
+      const NavigationID& navigation_id,
+      const base::TimeTicks& first_contentful_paint);
+
+ private:
+  friend class ResourcePrefetchPredictorBrowserTest;
+
+  FRIEND_TEST_ALL_PREFIXES(LoadingDataCollectorTest, HandledResourceTypes);
+
+  // Returns true if the main page request is supported for prediction.
+  static bool IsHandledMainPage(net::URLRequest* request);
+
+  // Returns true if the subresource request is supported for prediction.
+  static bool IsHandledSubresource(net::URLRequest* request,
+                                   content::ResourceType resource_type);
+
+  // Returns true if the subresource has a supported type.
+  static bool IsHandledResourceType(content::ResourceType resource_type,
+                                    const std::string& mime_type);
+
+  static void SetAllowPortInUrlsForTesting(bool state);
+
+  predictors::ResourcePrefetchPredictor* const predictor_;
+};
+
+}  // namespace predictors
+
+#endif  // CHROME_BROWSER_PREDICTORS_LOADING_DATA_COLLECTOR_H_