predictors: move ResourcePrefetcher handling to LoadingPredictor.

chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc

 // 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.
 
 #include <algorithm>
 #include <cstddef>
 #include <set>
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
@@ skipping 270 matching lines @@
   bool match_navigation_id_;
   bool match_before_first_contentful_paint_;
   std::set<NavigationID> current_navigation_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(LearningObserver);
 };
 
 // Helper class to track and allow waiting for a single OnPrefetchingFinished
 // event. Checks also that {Start,Stop}Prefetching are called with the right
 // argument.
-class PrefetchingObserver : public TestObserver {
+class PrefetchingObserver : public TestLoadingObserver {
  public:
-  PrefetchingObserver(ResourcePrefetchPredictor* predictor,
-                      const GURL& expected_main_frame_url,
-                      bool is_learning_allowed)
-      : TestObserver(predictor),
-        main_frame_url_(expected_main_frame_url),
-        is_learning_allowed_(is_learning_allowed) {}
+  PrefetchingObserver(LoadingPredictor* predictor,
+                      const GURL& expected_main_frame_url)
+      : TestLoadingObserver(predictor),
+        main_frame_url_(expected_main_frame_url) {}
 
-  // TestObserver:
-  void OnNavigationLearned(size_t url_visit_count,

[alexilin, 2017/07/03 14:55:02]

It's not really good that we throw this check away. Could you add a
TODO(alexilin) to revisit it later?

[Benoit L, 2017/07/03 15:43:15]

Done.

-                           const PageRequestSummary& summary) override {
-    if (!is_learning_allowed_)
-      ADD_FAILURE() << "Prefetching shouldn't activate learning";
-  }
-
+  // LoadingTestObserver:
   void OnPrefetchingStarted(const GURL& main_frame_url) override {
     EXPECT_EQ(main_frame_url_, main_frame_url);
   }
 
   void OnPrefetchingStopped(const GURL& main_frame_url) override {
     EXPECT_EQ(main_frame_url_, main_frame_url);
   }
 
   void OnPrefetchingFinished(const GURL& main_frame_url) override {
     EXPECT_EQ(main_frame_url_, main_frame_url);
     run_loop_.Quit();
   }
 
   void Wait() { run_loop_.Run(); }
 
  private:
   base::RunLoop run_loop_;
   GURL main_frame_url_;
-  bool is_learning_allowed_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefetchingObserver);
 };
 
 class ResourcePrefetchPredictorBrowserTest : public InProcessBrowserTest {
  protected:
   using URLRequestSummary = ResourcePrefetchPredictor::URLRequestSummary;
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
     command_line->AppendSwitchASCII("force-fieldtrials", "trial/group");
@@ skipping 103 matching lines @@
 
     for (auto& kv : resources_) {
       if (kv.second.is_observable)
         kv.second.request.was_cached = true;
     }
     for (const auto& nav : observer.current_navigation_ids())
       navigation_id_history_.insert(nav);
   }
 
   void NavigateToURLAndCheckPrefetching(const GURL& main_frame_url) {
-    PrefetchingObserver observer(resource_prefetch_predictor_, main_frame_url,
-                                 true);
+    PrefetchingObserver observer(predictor_, main_frame_url);
     ui_test_utils::NavigateToURL(browser(), main_frame_url);
     observer.Wait();
     for (auto& kv : resources_) {
       if (kv.second.is_observable)
         kv.second.request.was_cached = true;
     }
   }
 
   void PrefetchURL(const GURL& main_frame_url) {
-    PrefetchingObserver observer(resource_prefetch_predictor_, main_frame_url,
-                                 false);
+    PrefetchingObserver observer(predictor_, main_frame_url);
     predictor_->PrepareForPageLoad(main_frame_url, HintOrigin::EXTERNAL);
     observer.Wait();
     for (auto& kv : resources_) {
       if (kv.second.is_observable)
         kv.second.request.was_cached = true;
     }
   }
 
   void TryToPrefetchURL(const GURL& main_frame_url) {
     predictor_->PrepareForPageLoad(main_frame_url, HintOrigin::EXTERNAL);
@@ skipping 537 matching lines @@
   AddResourcesFromSubresourceHtml();
 
   NavigateToURLAndCheckSubresources(initial_url);
   ClearCache();
   NavigateToURLAndCheckSubresources(initial_url);
   ClearCache();
   NavigateToURLAndCheckPrefetching(initial_url);
 }
 
 }  // namespace predictors