predictors: Add precision / recall histograms for speculative prefetch.

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>
 
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/run_loop.h"
+#include "base/test/histogram_tester.h"
 #include "base/time/time.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor_tables.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor_test_util.h"
 #include "chrome/test/base/testing_profile.h"
 #include "components/history/core/browser/history_service.h"
 #include "components/history/core/browser/history_types.h"
 #include "components/sessions/core/session_id.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/common/previews_state.h"
@@ skipping 234 matching lines @@
 
   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_;
+
+  std::unique_ptr<base::HistogramTester> histogram_tester_;
 };
 
 ResourcePrefetchPredictorTest::ResourcePrefetchPredictorTest()
     : thread_bundle_(),
       profile_(new TestingProfile()),
       mock_tables_(new StrictMock<MockResourcePrefetchPredictorTables>()),
       empty_resource_data_(),
       empty_redirect_data_() {}
 
 ResourcePrefetchPredictorTest::~ResourcePrefetchPredictorTest() {
@@ skipping 16 matching lines @@
               GetAllData(Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(PrefetchDataMap())),
                          Pointee(ContainerEq(RedirectDataMap())),
                          Pointee(ContainerEq(RedirectDataMap()))));
   InitializePredictor();
   EXPECT_TRUE(predictor_->inflight_navigations_.empty());
   EXPECT_EQ(predictor_->initialization_state_,
             ResourcePrefetchPredictor::INITIALIZED);
 
   url_request_context_.set_job_factory(&url_request_job_factory_);
+
+  histogram_tester_.reset(new base::HistogramTester());
 }
 
 void ResourcePrefetchPredictorTest::TearDown() {
   predictor_.reset(NULL);
   profile_->DestroyHistoryService();
 }
 
 void ResourcePrefetchPredictorTest::InitializeSampleData() {
   {  // Url data.
     PrefetchData google = CreatePrefetchData("http://www.google.com/", 1);
@@ skipping 1232 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, TestPrecisionRecallHistograms) {
+  using testing::_;
+  EXPECT_CALL(*mock_tables_.get(), UpdateData(_, _, _, _));
+
+  // Fill the database with 3 resources: 1 useful, 2 useless.
+  const std::string main_frame_url = "http://google.com/?query=cats";
+  PrefetchData google = CreatePrefetchData("google.com", 1);
+
+  const std::string script_url = "https://cdn.google.com/script.js";
+  InitializeResourceData(google.add_resources(), script_url,
+                         content::RESOURCE_TYPE_SCRIPT, 10, 0, 1, 2.1,
+                         net::MEDIUM, false, false);
+  InitializeResourceData(google.add_resources(), script_url + "foo",
+                         content::RESOURCE_TYPE_SCRIPT, 10, 0, 1, 2.1,
+                         net::MEDIUM, false, false);
+  InitializeResourceData(google.add_resources(), script_url + "bar",
+                         content::RESOURCE_TYPE_SCRIPT, 10, 0, 1, 2.1,
+                         net::MEDIUM, false, false);
+  predictor_->host_table_cache_->insert(
+      std::make_pair(google.primary_key(), google));
+
+  std::vector<GURL> urls;
+  EXPECT_TRUE(predictor_->GetPrefetchData(GURL(main_frame_url), &urls));
+
+  // Simulate a navigation with 2 resources, one we know, one we don't.
+  URLRequestSummary main_frame = CreateURLRequestSummary(1, main_frame_url);
+  predictor_->RecordURLRequest(main_frame);
+
+  URLRequestSummary script = CreateURLRequestSummary(
+      1, main_frame_url, script_url, content::RESOURCE_TYPE_SCRIPT);
+  predictor_->RecordURLResponse(script);
+
+  URLRequestSummary new_script = CreateURLRequestSummary(
+      1, main_frame_url, script_url + "2", content::RESOURCE_TYPE_SCRIPT);
+  predictor_->RecordURLResponse(new_script);
+
+  predictor_->RecordMainFrameLoadComplete(main_frame.navigation_id);
+  profile_->BlockUntilHistoryProcessesPendingRequests();
+
+  histogram_tester_->ExpectBucketCount(
+      internal::kResourcePrefetchPredictorRecallHistogram, 50, 1);
+  histogram_tester_->ExpectBucketCount(
+      internal::kResourcePrefetchPredictorPrecisionHistogram, 33, 1);
+}
+
 }  // namespace predictors