predictors: Make ResourcePrefetchPredictor observable.

chrome/browser/predictors/resource_prefetch_predictor_unittest.cc

 // Copyright 2014 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 "chrome/browser/predictors/resource_prefetch_predictor.h"
 
 #include <iostream>
 #include <memory>
 #include <utility>
 
@@ skipping 17 matching lines @@
 #include "testing/gtest/include/gtest/gtest.h"
 
 using testing::ContainerEq;
 using testing::Pointee;
 using testing::SetArgPointee;
 using testing::StrictMock;
 using testing::UnorderedElementsAre;
 
 namespace predictors {
 
-typedef ResourcePrefetchPredictor::URLRequestSummary URLRequestSummary;
-typedef ResourcePrefetchPredictorTables::PrefetchDataMap PrefetchDataMap;
-typedef ResourcePrefetchPredictorTables::RedirectDataMap RedirectDataMap;
+using URLRequestSummary = ResourcePrefetchPredictor::URLRequestSummary;
+using PageRequestSummary = ResourcePrefetchPredictor::PageRequestSummary;
+using PrefetchDataMap = ResourcePrefetchPredictorTables::PrefetchDataMap;
+using RedirectDataMap = ResourcePrefetchPredictorTables::RedirectDataMap;
 
 scoped_refptr<net::HttpResponseHeaders> MakeResponseHeaders(
     const char* headers) {
   return make_scoped_refptr(new net::HttpResponseHeaders(
       net::HttpUtil::AssembleRawHeaders(headers, strlen(headers))));
 }
 
 class EmptyURLRequestDelegate : public net::URLRequest::Delegate {
   void OnResponseStarted(net::URLRequest* request, int net_error) override {}
   void OnReadCompleted(net::URLRequest* request, int bytes_read) override {}
@@ skipping 95 matching lines @@
                void(const std::vector<std::string>& urls,
                     const std::vector<std::string>& hosts));
   MOCK_METHOD2(DeleteSingleRedirectDataPoint,
                void(const std::string& key, PrefetchKeyType key_type));
   MOCK_METHOD0(DeleteAllData, void());
 
  protected:
   ~MockResourcePrefetchPredictorTables() { }
 };
 
+class MockResourcePrefetchPredictorObserver
+    : public ResourcePrefetchPredictor::TestObserver {
+ public:
+  MockResourcePrefetchPredictorObserver(ResourcePrefetchPredictor* predictor)
+      : TestObserver(predictor) {}
+
+  MOCK_METHOD2(
+      OnNavigationLearned,
+      void(size_t url_visit_count,
+           const ResourcePrefetchPredictor::PageRequestSummary& summary));
+};
+
 class ResourcePrefetchPredictorTest : public testing::Test {
  public:
   ResourcePrefetchPredictorTest();
   ~ResourcePrefetchPredictorTest() override;
   void SetUp() override;
   void TearDown() override;
 
  protected:
   void AddUrlToHistory(const std::string& url, int visit_count) {
     HistoryServiceFactory::GetForProfile(profile_.get(),
@@ skipping 11 matching lines @@
 
   NavigationID CreateNavigationID(int process_id,
                                   int render_frame_id,
                                   const std::string& main_frame_url) {
     NavigationID navigation_id(process_id, render_frame_id,
                                GURL(main_frame_url));
     navigation_id.creation_time = base::TimeTicks::Now();
     return navigation_id;
   }
 
+  PageRequestSummary CreatePageRequestSummary(
+      const std::string& main_frame_url,
+      const std::string& initial_url,
+      const std::vector<URLRequestSummary>& subresource_requests) {
+    GURL main_frame_gurl(main_frame_url);
+    PageRequestSummary summary(main_frame_gurl);
+    summary.initial_url = GURL(initial_url);
+    summary.subresource_requests = subresource_requests;
+    return summary;
+  }
+
   URLRequestSummary CreateURLRequestSummary(
       int process_id,
       int render_frame_id,
       const std::string& main_frame_url,
       const std::string& resource_url = std::string(),
       content::ResourceType resource_type = content::RESOURCE_TYPE_MAIN_FRAME,
       net::RequestPriority priority = net::MEDIUM,
       const std::string& mime_type = std::string(),
       bool was_cached = false) {
     URLRequestSummary summary;
@@ skipping 60 matching lines @@
     config.min_url_visit_count = 2;
     config.max_resources_per_entry = 4;
     config.max_consecutive_misses = 2;
     config.min_resource_confidence_to_trigger_prefetch = 0.5;
 
     // TODO(shishir): Enable the prefetching mode in the tests.
     config.mode |= ResourcePrefetchPredictorConfig::URL_LEARNING;
     config.mode |= ResourcePrefetchPredictorConfig::HOST_LEARNING;
     predictor_.reset(new ResourcePrefetchPredictor(config, profile_.get()));
     predictor_->set_mock_tables(mock_tables_);
+    mock_observer_.reset(new StrictMock<MockResourcePrefetchPredictorObserver>(

[pasko, 2016/10/24 17:59:38]

If there is a ResetPredictor() somewhere in the test, what happens with an
EXPECT_CALL(*mock_observer_.get(), ...) that was issued before it?

The approach with mock_tables_ seems to be working because this object is not
swapped, just re-attached to the new ResourcePrefetchPredictor on every
ResetPredictor(). Seems like consistency here would eliminate unpleasant
surprises. Would be nice.

[pasko, 2016/10/24 17:59:38]

It would be nice to avoid this having a 'global' mock_observer_ for all tests
with complicated resetting, registration and deregistration, friendship between
the TestObserver and the ResourcePrefetchPredictor.

I suspect it is not really important to hook into LearnNavigation between resets
of the ResourcePrefetchPredictor (not sure here, there could be reasons, let me
know).

We could instead have a std::unique_ptr<MockTestObserver> in each test that
needs the hook, and the hook would de-register itself in its destructor. The
constructor for such observer _could_ take expected learnings as a parameter,
which can be EXPECT-ed in the destructor. This still has the flexibility of
.reset() on the observer to perform the checks and installing the new observer.
This way the two classes would avoid tight coupling: for the predictor, the
observer is just a pointer - minimal code in production.

[alexilin, 2016/10/25 11:38:09]

Yeah, it's a kind of dangerous situation.
Let's try to rewrite it.

All control happens in a single thread so there won't be any race conditions
between resets.

I don't want reinvent EXPECT_CALL and pass expected arguments as parameters of
the mock class constructor. 

[pasko, 2016/10/25 14:05:40]

this latter sgtm

[alexilin, 2016/10/25 15:10:58]

Done.

+        predictor_.get()));
   }
 
   void InitializeSampleData();
 
   content::TestBrowserThreadBundle thread_bundle_;
   std::unique_ptr<TestingProfile> profile_;
   net::TestURLRequestContext url_request_context_;
 
   std::unique_ptr<ResourcePrefetchPredictor> predictor_;
   scoped_refptr<StrictMock<MockResourcePrefetchPredictorTables> > mock_tables_;
+  std::unique_ptr<StrictMock<MockResourcePrefetchPredictorObserver>>
+      mock_observer_;
 
   PrefetchDataMap test_url_data_;
   PrefetchDataMap test_host_data_;
   RedirectDataMap test_url_redirect_data_;
   RedirectDataMap test_host_redirect_data_;
   PrefetchData empty_resource_data_;
   RedirectData empty_redirect_data_;
 
   MockURLRequestJobFactory url_request_job_factory_;
   EmptyURLRequestDelegate url_request_delegate_;
@@ skipping 185 matching lines @@
   EXPECT_TRUE(predictor_->inflight_navigations_.empty());
 
   EXPECT_EQ(test_url_data_, *predictor_->url_table_cache_);
   EXPECT_EQ(test_host_data_, *predictor_->host_table_cache_);
   EXPECT_EQ(test_url_redirect_data_, *predictor_->url_redirect_table_cache_);
   EXPECT_EQ(test_host_redirect_data_, *predictor_->host_redirect_table_cache_);
 }
 
 // Single navigation but history count is low, so should not record.
 TEST_F(ResourcePrefetchPredictorTest, NavigationNotRecorded) {
-  AddUrlToHistory("http://www.google.com", 1);
+  const int kVisitCount = 1;
+  AddUrlToHistory("https://www.google.com", kVisitCount);
 
   URLRequestSummary main_frame =
       CreateURLRequestSummary(1, 1, "http://www.google.com");
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1U, predictor_->inflight_navigations_.size());
 
   URLRequestSummary main_frame_redirect = CreateRedirectRequestSummary(
       1, 1, "http://www.google.com", "https://www.google.com");
   predictor_->RecordURLRedirect(main_frame_redirect);
   EXPECT_EQ(1U, predictor_->inflight_navigations_.size());
   main_frame = CreateURLRequestSummary(1, 1, "https://www.google.com");
 
   // Now add a few subresources.
   URLRequestSummary resource1 = CreateURLRequestSummary(
       1, 1, "https://www.google.com", "https://google.com/style1.css",
       content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", false);
   predictor_->RecordURLResponse(resource1);
   URLRequestSummary resource2 = CreateURLRequestSummary(
       1, 1, "https://www.google.com", "https://google.com/script1.js",
       content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false);
   predictor_->RecordURLResponse(resource2);
   URLRequestSummary resource3 = CreateURLRequestSummary(
       1, 1, "https://www.google.com", "https://google.com/script2.js",
       content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false);
   predictor_->RecordURLResponse(resource3);
 
+  EXPECT_CALL(
+      *mock_observer_.get(),
+      OnNavigationLearned(kVisitCount,
+                          CreatePageRequestSummary(
+                              "https://www.google.com", "http://www.google.com",
+                              {resource1, resource2, resource3})));
+
   PrefetchData host_data = CreatePrefetchData("www.google.com");
   InitializeResourceData(host_data.add_resources(),
                          "https://google.com/style1.css",
                          content::RESOURCE_TYPE_STYLESHEET, 1, 0, 0, 1.0,
                          net::MEDIUM, false, false);
   InitializeResourceData(
       host_data.add_resources(), "https://google.com/script1.js",
       content::RESOURCE_TYPE_SCRIPT, 1, 0, 0, 2.0, net::MEDIUM, false, false);
   InitializeResourceData(
       host_data.add_resources(), "https://google.com/script2.js",
       content::RESOURCE_TYPE_SCRIPT, 1, 0, 0, 3.0, net::MEDIUM, false, false);
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(empty_resource_data_, host_data, empty_redirect_data_,
                          empty_redirect_data_));
 
   predictor_->RecordMainFrameLoadComplete(main_frame.navigation_id);
   profile_->BlockUntilHistoryProcessesPendingRequests();
 }
 
 // Single navigation that will be recorded. Will check for duplicate
 // resources and also for number of resources saved.
 TEST_F(ResourcePrefetchPredictorTest, NavigationUrlNotInDB) {
-  AddUrlToHistory("http://www.google.com", 4);
+  const int kVisitCount = 4;
+  AddUrlToHistory("http://www.google.com", kVisitCount);
 
   URLRequestSummary main_frame =
       CreateURLRequestSummary(1, 1, "http://www.google.com");
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1U, predictor_->inflight_navigations_.size());
 
-  URLRequestSummary resource1 = CreateURLRequestSummary(
+  std::vector<URLRequestSummary> resources;
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/style1.css",
-      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", false);
-  predictor_->RecordURLResponse(resource1);
-  URLRequestSummary resource2 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/script1.js",
-      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false);
-  predictor_->RecordURLResponse(resource2);
-  URLRequestSummary resource3 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/script2.js",
-      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false);
-  predictor_->RecordURLResponse(resource3);
-  URLRequestSummary resource4 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/script1.js",
-      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", true);
-  predictor_->RecordURLResponse(resource4);
-  URLRequestSummary resource5 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", true));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/image1.png",
-      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false);
-  predictor_->RecordURLResponse(resource5);
-  URLRequestSummary resource6 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/image2.png",
-      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false);
-  predictor_->RecordURLResponse(resource6);
-  URLRequestSummary resource7 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/style2.css",
-      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", true);
-  predictor_->RecordURLResponse(resource7);
+      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", true));
+  predictor_->RecordURLResponse(resources.back());
+
+  EXPECT_CALL(*mock_observer_.get(),
+              OnNavigationLearned(
+                  kVisitCount, CreatePageRequestSummary("http://www.google.com",
+                                                        "http://www.google.com",
+                                                        resources)));
 
   PrefetchData url_data = CreatePrefetchData("http://www.google.com/");
   InitializeResourceData(url_data.add_resources(),
                          "http://google.com/style1.css",
                          content::RESOURCE_TYPE_STYLESHEET, 1, 0, 0, 1.0,
                          net::MEDIUM, false, false);
   InitializeResourceData(
       url_data.add_resources(), "http://google.com/script1.js",
       content::RESOURCE_TYPE_SCRIPT, 1, 0, 0, 2.0, net::MEDIUM, false, false);
   InitializeResourceData(
       url_data.add_resources(), "http://google.com/script2.js",
       content::RESOURCE_TYPE_SCRIPT, 1, 0, 0, 3.0, net::MEDIUM, false, false);
   InitializeResourceData(url_data.add_resources(),
                          "http://google.com/style2.css",
                          content::RESOURCE_TYPE_STYLESHEET, 1, 0, 0, 7.0,
                          net::MEDIUM, false, false);
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(url_data, empty_resource_data_, empty_redirect_data_,
                          empty_redirect_data_));
 
   PrefetchData host_data = CreatePrefetchData("www.google.com");
   host_data.mutable_resources()->CopyFrom(url_data.resources());
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(empty_resource_data_, host_data, empty_redirect_data_,
                          empty_redirect_data_));
 
-  predictor_->OnNavigationComplete(main_frame.navigation_id);
+  predictor_->RecordMainFrameLoadComplete(main_frame.navigation_id);
   profile_->BlockUntilHistoryProcessesPendingRequests();
 }
 
 // Tests that navigation is recorded correctly for URL already present in
 // the database cache.
 TEST_F(ResourcePrefetchPredictorTest, NavigationUrlInDB) {
-  AddUrlToHistory("http://www.google.com", 4);
+  const int kVisitCount = 4;
+  AddUrlToHistory("http://www.google.com", kVisitCount);
 
   EXPECT_CALL(*mock_tables_.get(),
               GetAllData(Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(RedirectDataMap())),
                          Pointee(ContainerEq(RedirectDataMap()))))
       .WillOnce(DoAll(SetArgPointee<0>(test_url_data_),
                       SetArgPointee<1>(test_host_data_)));
   ResetPredictor();
   InitializePredictor();
   EXPECT_EQ(3U, predictor_->url_table_cache_->size());
   EXPECT_EQ(2U, predictor_->host_table_cache_->size());
 
   URLRequestSummary main_frame = CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://www.google.com",
       content::RESOURCE_TYPE_MAIN_FRAME, net::MEDIUM, std::string(), false);
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1U, predictor_->inflight_navigations_.size());
 
-  URLRequestSummary resource1 = CreateURLRequestSummary(
+  std::vector<URLRequestSummary> resources;
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/style1.css",
-      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", false);
-  predictor_->RecordURLResponse(resource1);
-  URLRequestSummary resource2 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/script1.js",
-      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false);
-  predictor_->RecordURLResponse(resource2);
-  URLRequestSummary resource3 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/script2.js",
-      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false);
-  predictor_->RecordURLResponse(resource3);
-  URLRequestSummary resource4 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/script1.js",
-      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", true);
-  predictor_->RecordURLResponse(resource4);
-  URLRequestSummary resource5 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_SCRIPT, net::MEDIUM, "text/javascript", true));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/image1.png",
-      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false);
-  predictor_->RecordURLResponse(resource5);
-  URLRequestSummary resource6 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/image2.png",
-      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false);
-  predictor_->RecordURLResponse(resource6);
-  URLRequestSummary resource7 = CreateURLRequestSummary(
+      content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false));
+  predictor_->RecordURLResponse(resources.back());
+  resources.push_back(CreateURLRequestSummary(
       1, 1, "http://www.google.com", "http://google.com/style2.css",
-      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", true);
-  predictor_->RecordURLResponse(resource7);
+      content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", true));
+  predictor_->RecordURLResponse(resources.back());
+
+  EXPECT_CALL(*mock_observer_.get(),
+              OnNavigationLearned(
+                  kVisitCount, CreatePageRequestSummary("http://www.google.com",
+                                                        "http://www.google.com",
+                                                        resources)));
 
   PrefetchData url_data = CreatePrefetchData("http://www.google.com/");
   InitializeResourceData(url_data.add_resources(),
                          "http://google.com/style1.css",
                          content::RESOURCE_TYPE_STYLESHEET, 4, 2, 0, 1.0,
                          net::MEDIUM, false, false);
   InitializeResourceData(
       url_data.add_resources(), "http://google.com/script1.js",
       content::RESOURCE_TYPE_SCRIPT, 1, 0, 0, 2.0, net::MEDIUM, false, false);
   InitializeResourceData(
@@ skipping 21 matching lines @@
       host_data.add_resources(), "http://google.com/script2.js",
       content::RESOURCE_TYPE_SCRIPT, 1, 0, 0, 3.0, net::MEDIUM, false, false);
   InitializeResourceData(host_data.add_resources(),
                          "http://google.com/style2.css",
                          content::RESOURCE_TYPE_STYLESHEET, 1, 0, 0, 7.0,
                          net::MEDIUM, false, false);
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(empty_resource_data_, host_data, empty_redirect_data_,
                          empty_redirect_data_));
 
-  predictor_->OnNavigationComplete(main_frame.navigation_id);
+  predictor_->RecordMainFrameLoadComplete(main_frame.navigation_id);
   profile_->BlockUntilHistoryProcessesPendingRequests();
 }
 
 // Tests that a URL is deleted before another is added if the cache is full.
 TEST_F(ResourcePrefetchPredictorTest, NavigationUrlNotInDBAndDBFull) {
-  AddUrlToHistory("http://www.nike.com/", 4);
+  const int kVisitCount = 4;
+  AddUrlToHistory("http://www.nike.com/", kVisitCount);
 
   EXPECT_CALL(*mock_tables_.get(),
               GetAllData(Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(RedirectDataMap())),
                          Pointee(ContainerEq(RedirectDataMap()))))
       .WillOnce(DoAll(SetArgPointee<0>(test_url_data_),
                       SetArgPointee<1>(test_host_data_)));
   ResetPredictor();
   InitializePredictor();
   EXPECT_EQ(3U, predictor_->url_table_cache_->size());
   EXPECT_EQ(2U, predictor_->host_table_cache_->size());
 
   URLRequestSummary main_frame = CreateURLRequestSummary(
       1, 1, "http://www.nike.com", "http://www.nike.com",
       content::RESOURCE_TYPE_MAIN_FRAME, net::MEDIUM, std::string(), false);
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1U, predictor_->inflight_navigations_.size());
 
   URLRequestSummary resource1 = CreateURLRequestSummary(
       1, 1, "http://www.nike.com", "http://nike.com/style1.css",
       content::RESOURCE_TYPE_STYLESHEET, net::MEDIUM, "text/css", false);
   predictor_->RecordURLResponse(resource1);
   URLRequestSummary resource2 = CreateURLRequestSummary(
       1, 1, "http://www.nike.com", "http://nike.com/image2.png",
       content::RESOURCE_TYPE_IMAGE, net::MEDIUM, "image/png", false);
   predictor_->RecordURLResponse(resource2);
 
+  EXPECT_CALL(*mock_observer_.get(),
+              OnNavigationLearned(
+                  kVisitCount, CreatePageRequestSummary(
+                                   "http://www.nike.com", "http://www.nike.com",
+                                   {resource1, resource2})));
+
   EXPECT_CALL(*mock_tables_.get(),
               DeleteSingleResourceDataPoint("http://www.google.com/",
                                             PREFETCH_KEY_TYPE_URL));
   EXPECT_CALL(*mock_tables_.get(),
               DeleteSingleResourceDataPoint("www.facebook.com",
                                             PREFETCH_KEY_TYPE_HOST));
 
   PrefetchData url_data = CreatePrefetchData("http://www.nike.com/");
   InitializeResourceData(url_data.add_resources(), "http://nike.com/style1.css",
                          content::RESOURCE_TYPE_STYLESHEET, 1, 0, 0, 1.0,
                          net::MEDIUM, false, false);
   InitializeResourceData(url_data.add_resources(), "http://nike.com/image2.png",
                          content::RESOURCE_TYPE_IMAGE, 1, 0, 0, 2.0,
                          net::MEDIUM, false, false);
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(url_data, empty_resource_data_, empty_redirect_data_,
                          empty_redirect_data_));
 
   PrefetchData host_data = CreatePrefetchData("www.nike.com");
   host_data.mutable_resources()->CopyFrom(url_data.resources());
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(empty_resource_data_, host_data, empty_redirect_data_,
                          empty_redirect_data_));
 
-  predictor_->OnNavigationComplete(main_frame.navigation_id);
+  predictor_->RecordMainFrameLoadComplete(main_frame.navigation_id);
   profile_->BlockUntilHistoryProcessesPendingRequests();
 }
 
 TEST_F(ResourcePrefetchPredictorTest, RedirectUrlNotInDB) {
-  AddUrlToHistory("https://facebook.com/google", 4);
+  const int kVisitCount = 4;
+  AddUrlToHistory("https://facebook.com/google", kVisitCount);
 
   URLRequestSummary fb1 = CreateURLRequestSummary(1, 1, "http://fb.com/google");
   predictor_->RecordURLRequest(fb1);
   EXPECT_EQ(1U, predictor_->inflight_navigations_.size());
 
   URLRequestSummary fb2 = CreateRedirectRequestSummary(
       1, 1, "http://fb.com/google", "http://facebook.com/google");
   predictor_->RecordURLRedirect(fb2);
   URLRequestSummary fb3 = CreateRedirectRequestSummary(
       1, 1, "http://facebook.com/google", "https://facebook.com/google");
   predictor_->RecordURLRedirect(fb3);
   NavigationID fb_end = CreateNavigationID(1, 1, "https://facebook.com/google");
 
+  EXPECT_CALL(
+      *mock_observer_.get(),
+      OnNavigationLearned(kVisitCount, CreatePageRequestSummary(
+                                           "https://facebook.com/google",
+                                           "http://fb.com/google",
+                                           std::vector<URLRequestSummary>())));
+
   // Since the navigation hasn't resources, corresponding entry
   // in resource table will be deleted.
   EXPECT_CALL(*mock_tables_.get(),
               DeleteSingleResourceDataPoint("https://facebook.com/google",
                                             PREFETCH_KEY_TYPE_URL));
   EXPECT_CALL(*mock_tables_.get(), DeleteSingleResourceDataPoint(
                                        "facebook.com", PREFETCH_KEY_TYPE_HOST));
 
   RedirectData url_redirect_data = CreateRedirectData("http://fb.com/google");
   InitializeRedirectStat(url_redirect_data.add_redirect_endpoints(),
                          "https://facebook.com/google", 1, 0, 0);
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(empty_resource_data_, empty_resource_data_,
                          url_redirect_data, empty_redirect_data_));
 
   RedirectData host_redirect_data = CreateRedirectData("fb.com");
   InitializeRedirectStat(host_redirect_data.add_redirect_endpoints(),
                          "facebook.com", 1, 0, 0);
   EXPECT_CALL(*mock_tables_.get(),
               UpdateData(empty_resource_data_, empty_resource_data_,
                          empty_redirect_data_, host_redirect_data));
 
   predictor_->RecordMainFrameLoadComplete(fb_end);
   profile_->BlockUntilHistoryProcessesPendingRequests();
 }
 
 // Tests that redirect is recorded correctly for URL already present in
 // the database cache.
 TEST_F(ResourcePrefetchPredictorTest, RedirectUrlInDB) {
-  AddUrlToHistory("https://facebook.com/google", 4);
+  const int kVisitCount = 7;
+  AddUrlToHistory("https://facebook.com/google", kVisitCount);
 
   EXPECT_CALL(*mock_tables_.get(),
               GetAllData(Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(RedirectDataMap())),
                          Pointee(ContainerEq(RedirectDataMap()))))
       .WillOnce(DoAll(SetArgPointee<2>(test_url_redirect_data_),
                       SetArgPointee<3>(test_host_redirect_data_)));
   ResetPredictor();
   InitializePredictor();
   EXPECT_EQ(3U, predictor_->url_redirect_table_cache_->size());
   EXPECT_EQ(2U, predictor_->host_redirect_table_cache_->size());
 
   URLRequestSummary fb1 = CreateURLRequestSummary(1, 1, "http://fb.com/google");
   predictor_->RecordURLRequest(fb1);
   EXPECT_EQ(1U, predictor_->inflight_navigations_.size());
 
   URLRequestSummary fb2 = CreateRedirectRequestSummary(
       1, 1, "http://fb.com/google", "http://facebook.com/google");
   predictor_->RecordURLRedirect(fb2);
   URLRequestSummary fb3 = CreateRedirectRequestSummary(
       1, 1, "http://facebook.com/google", "https://facebook.com/google");
   predictor_->RecordURLRedirect(fb3);
   NavigationID fb_end = CreateNavigationID(1, 1, "https://facebook.com/google");
 
+  EXPECT_CALL(
+      *mock_observer_.get(),
+      OnNavigationLearned(kVisitCount, CreatePageRequestSummary(
+                                           "https://facebook.com/google",
+                                           "http://fb.com/google",
+                                           std::vector<URLRequestSummary>())));
+
   // Oldest entries in tables will be superseded and deleted.
   EXPECT_CALL(*mock_tables_.get(),
               DeleteSingleRedirectDataPoint("bbc.com", PREFETCH_KEY_TYPE_HOST));
 
   // Since the navigation hasn't resources, corresponding entry
   // in resource table will be deleted.
   EXPECT_CALL(*mock_tables_.get(),
               DeleteSingleResourceDataPoint("https://facebook.com/google",
                                             PREFETCH_KEY_TYPE_URL));
   EXPECT_CALL(*mock_tables_.get(), DeleteSingleResourceDataPoint(
@@ skipping 660 matching lines @@
                          content::RESOURCE_TYPE_FONT_RESOURCE, 10, 0, 1, 2.1,
                          net::MEDIUM, false, false);
   predictor_->url_table_cache_->insert(
       std::make_pair(www_google_url.primary_key(), www_google_url));
 
   urls.clear();
   EXPECT_TRUE(predictor_->GetPrefetchData(main_frame_url, &urls));
   EXPECT_THAT(urls, UnorderedElementsAre(GURL(font_url)));
 }
 
+TEST_F(ResourcePrefetchPredictorTest, SetObserverForTesting) {
+  std::unique_ptr<ResourcePrefetchPredictor> predictor =
+      base::MakeUnique<ResourcePrefetchPredictor>(predictor_->config_,
+                                                  predictor_->profile_);
+
+  // Test that observer is created correctly.
+  MockResourcePrefetchPredictorObserver observer1(predictor.get());
+  EXPECT_EQ(observer1.predictor_, predictor.get());
+  EXPECT_EQ(predictor->observer_, &observer1);
+
+  // Test that observer is superseded correctly.
+  MockResourcePrefetchPredictorObserver observer2(predictor.get());
+  EXPECT_EQ(observer2.predictor_, predictor.get());
+  EXPECT_EQ(predictor->observer_, &observer2);
+  EXPECT_EQ(observer1.predictor_, nullptr);
+
+  // Test that observer imforms predictor about its death.

[pasko, 2016/10/24 17:59:38]

nit: s/imforms/informs/

[alexilin, 2016/10/25 11:38:09]

Done.

+  {
+    MockResourcePrefetchPredictorObserver observer3(predictor.get());
+    EXPECT_EQ(observer3.predictor_, predictor.get());
+    EXPECT_EQ(predictor->observer_, &observer3);
+  }
+  EXPECT_EQ(predictor->observer_, nullptr);
+
+  // Test that predictor informs observer about its death.
+  MockResourcePrefetchPredictorObserver observer4(predictor.get());
+  EXPECT_EQ(observer4.predictor_, predictor.get());
+  EXPECT_EQ(predictor->observer_, &observer4);
+  predictor.reset();
+  EXPECT_EQ(observer4.predictor_, nullptr);
+}
+
 }  // namespace predictors