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

chrome/browser/predictors/glowplug_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_GLOWPLUG_COLLECTOR_H_
+#define CHROME_BROWSER_PREDICTORS_GLOWPLUG_COLLECTOR_H_
+
+#include "chrome/browser/predictors/resource_prefetch_predictor.h"
+#include "content/public/common/resource_type.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace predictors {
+
+using predictors::ResourcePrefetchPredictor;

[alexilin, 2017/05/22 13:20:36]

Please, remove aliases and use fully-qualified names instead.

Explanation:
"Do not use Namespace aliases at namespace scope in header files except in
explicitly marked internal-only namespaces, because anything imported into a
namespace in a header file becomes part of the public API exported by that
file."
https://google.github.io/styleguide/cppguide.html#Namespaces

[trevordixon, 2017/05/22 21:29:01]

Done.

+using URLRequestSummary =
+    predictors::ResourcePrefetchPredictor::URLRequestSummary;
+
+class GlowplugCollector : public base::SupportsWeakPtr<GlowplugCollector> {

[alexilin, 2017/05/22 13:20:36]

URLRequestSummary and other *Summary classes also should be moved outside of
resource_prefetch_predictor. And I'd prefer to not nest them inside of any
class.
I'm okay with doing that in forthcoming CL.

[alexilin, 2017/05/22 13:20:36]

This class needs the detailed description in a comment.

[trevordixon, 2017/05/22 21:29:01]

Done.

+ public:
+  GlowplugCollector(ResourcePrefetchPredictor* predictor);
+  ~GlowplugCollector();
+
+  // Thread safe.
+  static bool ShouldRecordRequest(net::URLRequest* request,
+                                  content::ResourceType resource_type);
+  static bool ShouldRecordResponse(net::URLRequest* response);
+  static bool ShouldRecordRedirect(net::URLRequest* response);
+
+  static void SetAllowPortInUrlsForTesting(bool state);
+
+  // 'ResourcePrefetchPredictorObserver' calls the below functions to inform the
+  // predictor of main frame and resource requests. Should only be called if the
+  // corresponding Should* functions return true.
+  void RecordURLRequest(const URLRequestSummary& request);
+  void RecordURLResponse(const URLRequestSummary& response);
+  void RecordURLRedirect(const 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:
+  predictors::ResourcePrefetchPredictor* const predictor_;
+};
+
+}  // namespace predictors
+
+#endif  // CHROME_BROWSER_PREDICTORS_GLOWPLUG_COLLECTOR_H_