Serve offline page for online URL on disconnected or bad networks

chrome/browser/android/offline_pages/offline_page_request_job_unittest.cc

Index: chrome/browser/android/offline_pages/offline_page_request_job_unittest.cc
diff --git a/chrome/browser/android/offline_pages/offline_page_request_job_unittest.cc b/chrome/browser/android/offline_pages/offline_page_request_job_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6d34d5962763479ef1e0e90e57b34d29d24c4285
--- /dev/null
+++ b/chrome/browser/android/offline_pages/offline_page_request_job_unittest.cc
@@ -0,0 +1,673 @@
+// 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 "chrome/browser/android/offline_pages/offline_page_request_job.h"
+
+#include "base/callback.h"
+#include "base/feature_list.h"
+#include "base/files/file_path.h"
+#include "base/memory/ptr_util.h"
+#include "base/message_loop/message_loop.h"
+#include "base/metrics/field_trial.h"
+#include "base/path_service.h"
+#include "base/run_loop.h"
+#include "base/test/histogram_tester.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "chrome/browser/android/offline_pages/offline_page_model_factory.h"
+#include "chrome/browser/android/offline_pages/offline_page_request_interceptor.h"
+#include "chrome/browser/android/offline_pages/offline_page_tab_helper.h"
+#include "chrome/browser/android/offline_pages/test_offline_page_model_builder.h"
+#include "chrome/common/chrome_paths.h"
+#include "chrome/test/base/testing_browser_process.h"
+#include "chrome/test/base/testing_profile.h"
+#include "chrome/test/base/testing_profile_manager.h"
+#include "components/offline_pages/client_namespace_constants.h"
+#include "components/offline_pages/offline_page_model.h"
+#include "components/previews/previews_experiments.h"
+#include "components/variations/variations_associated_data.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/resource_request_info.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/common/resource_type.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "net/nqe/network_quality_estimator.h"
+#include "net/url_request/url_request.h"
+#include "net/url_request/url_request_context.h"
+#include "net/url_request/url_request_intercepting_job_factory.h"
+#include "net/url_request/url_request_job_factory_impl.h"
+#include "net/url_request/url_request_test_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace offline_pages {
+
+namespace {
+
+const GURL kTestUrl("http://test.org/page1");
+const GURL kTestUrl2("http://test.org/page2");
+const ClientId kTestClientId = ClientId(kBookmarkNamespace, "1234");
+const int kTestFileSize = 444;
+const int kTabId = 1;
+const int kBufSize = 1024;
+const char kAggregatedRequestResultHistogram[] =
+    "OfflinePages.AggregatedRequestResult";
+
+class OfflinePageRequestJobTestDelegate :
+    public OfflinePageRequestJob::Delegate {
+ public:
+  OfflinePageRequestJobTestDelegate(content::WebContents* web_content,
+                                    int tab_id)
+      : web_content_(web_content),
+        tab_id_(tab_id) {}
+
+  content::ResourceRequestInfo::WebContentsGetter
+  GetWebContentsGetter(net::URLRequest* request) const override {
+    return base::Bind(&OfflinePageRequestJobTestDelegate::GetWebContents,
+                      web_content_);
+  }
+
+  OfflinePageRequestJob::Delegate::TabIdGetter GetTabIdGetter() const override {
+    return base::Bind(&OfflinePageRequestJobTestDelegate::GetTabId,
+                      tab_id_);
+  }
+
+ private:
+  static content::WebContents* GetWebContents(
+      content::WebContents* web_content) {
+    return web_content;
+  }
+
+  static bool GetTabId(
+      int tab_id_value, content::WebContents* web_content, int* tab_id) {
+    *tab_id = tab_id_value;
+    return true;
+  }
+
+  content::WebContents* web_content_;
+  int tab_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePageRequestJobTestDelegate);
+};
+
+class TestURLRequestDelegate : public net::URLRequest::Delegate {
+ public:
+  typedef base::Callback<void(int)> ReadCompletedCallback;
+
+  explicit TestURLRequestDelegate(const ReadCompletedCallback& callback)
+      : read_completed_callback_(callback),
+        buffer_(new net::IOBuffer(kBufSize)) {}
+
+  void OnResponseStarted(net::URLRequest* request) override {
+    if (!request->status().is_success()) {
+      read_completed_callback_.Run(0);
+      return;
+    }
+    int bytes_read = 0;
+    request->Read(buffer_.get(), kBufSize, &bytes_read);
+  }
+
+  void OnReadCompleted(net::URLRequest* request, int bytes_read) override {
+    if (!read_completed_callback_.is_null())
+      read_completed_callback_.Run(bytes_read);
+  }
+
+ private:
+  ReadCompletedCallback read_completed_callback_;
+  scoped_refptr<net::IOBuffer> buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestURLRequestDelegate);
+};
+
+class TestURLRequestInterceptingJobFactory
+    : public net::URLRequestInterceptingJobFactory {
+ public:
+  TestURLRequestInterceptingJobFactory(
+      std::unique_ptr<net::URLRequestJobFactory> job_factory,
+      std::unique_ptr<net::URLRequestInterceptor> interceptor,
+      content::WebContents* web_contents)
+      : net::URLRequestInterceptingJobFactory(
+            std::move(job_factory), std::move(interceptor)),
+        web_contents_(web_contents) {}
+  ~TestURLRequestInterceptingJobFactory() override {}
+
+  net::URLRequestJob* MaybeCreateJobWithProtocolHandler(
+      const std::string& scheme,
+      net::URLRequest* request,
+      net::NetworkDelegate* network_delegate) const override {
+    net::URLRequestJob* job = net::URLRequestInterceptingJobFactory::
+        MaybeCreateJobWithProtocolHandler(scheme, request, network_delegate);
+    if (job) {
+      static_cast<OfflinePageRequestJob*>(job)->SetDelegateForTesting(
+          base::MakeUnique<OfflinePageRequestJobTestDelegate>(
+              web_contents_, kTabId));
+    }
+    return job;
+  }
+
+ private:
+  content::WebContents* web_contents_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestURLRequestInterceptingJobFactory);
+};
+
+class TestNetworkChangeNotifier : public net::NetworkChangeNotifier {
+ public:
+  TestNetworkChangeNotifier() : online_(true) {}
+  ~TestNetworkChangeNotifier() override {}
+
+  net::NetworkChangeNotifier::ConnectionType GetCurrentConnectionType()
+      const override {
+    return online_ ? net::NetworkChangeNotifier::CONNECTION_UNKNOWN
+                   : net::NetworkChangeNotifier::CONNECTION_NONE;
+  }
+
+  void set_online(bool online) { online_ = online; }
+
+ private:
+  bool online_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestNetworkChangeNotifier);
+};
+
+class TestNetworkQualityEstimator : public net::NetworkQualityEstimator {
+ public:
+  explicit TestNetworkQualityEstimator(
+      const std::map<std::string, std::string>& variation_params)
+      : NetworkQualityEstimator(
+            std::unique_ptr<net::ExternalEstimateProvider>(),
+            variation_params),
+        effective_connection_type_(net::EFFECTIVE_CONNECTION_TYPE_UNKNOWN) {}
+  ~TestNetworkQualityEstimator() override {}
+
+  net::EffectiveConnectionType GetEffectiveConnectionType() const override {
+    return effective_connection_type_;
+  }
+
+  void set_effective_connection_type(
+      net::EffectiveConnectionType effective_connection_type) {
+    effective_connection_type_ = effective_connection_type;
+  }
+
+ private:
+  net::EffectiveConnectionType effective_connection_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestNetworkQualityEstimator);
+};
+
+class ScopedEnableProbihibitivelySlowNetwork {
+ public:
+  explicit ScopedEnableProbihibitivelySlowNetwork(
+      net::URLRequestContext* url_request_context)
+      : field_trial_list_(nullptr),
+        url_request_context_(url_request_context) {
+    previews::EnableOfflinePreviewsForTesting();
+
+    test_network_quality_estimator_ =
+        base::MakeUnique<TestNetworkQualityEstimator>
+            (network_quality_estimator_params_);
+    test_network_quality_estimator_->set_effective_connection_type(
+        net::EFFECTIVE_CONNECTION_TYPE_SLOW_2G);
+    url_request_context_->set_network_quality_estimator(
+        test_network_quality_estimator_.get());
+  }
+
+  ~ScopedEnableProbihibitivelySlowNetwork() {
+    url_request_context_->set_network_quality_estimator(nullptr);
+    variations::testing::ClearAllVariationParams();
+  }
+
+ private:
+  base::FieldTrialList field_trial_list_;
+  std::map<std::string, std::string> network_quality_estimator_params_;
+  std::unique_ptr<TestNetworkQualityEstimator> test_network_quality_estimator_;
+  net::URLRequestContext* url_request_context_;
+};
+
+class TestOfflinePageArchiver : public OfflinePageArchiver {
+ public:
+  TestOfflinePageArchiver(const GURL& url,
+                          const base::FilePath& archive_file_path)
+      : url_(url),
+        archive_file_path_(archive_file_path) {}
+  ~TestOfflinePageArchiver() override {}
+
+  void CreateArchive(const base::FilePath& archives_dir,
+                     int64_t archive_id,
+                     const CreateArchiveCallback& callback) override {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE,
+        base::Bind(callback, this, ArchiverResult::SUCCESSFULLY_CREATED,
+                   url_, archive_file_path_, base::string16(), kTestFileSize));
+  }
+
+ private:
+  const GURL url_;
+  const base::FilePath archive_file_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestOfflinePageArchiver);
+};
+
+}  // namespace
+
+class OfflinePageRequestJobTest : public testing::Test {
+ public:
+  OfflinePageRequestJobTest();
+  ~OfflinePageRequestJobTest() override {}
+
+  void SetUp() override;
+
+  void SimulateHasNetworkConnectivity(bool has_connectivity);
+  void RunUntilIdle();
+
+  void InterceptRequest(const GURL& url,
+                        const std::string& method,
+                        const std::string& extra_header_name,
+                        const std::string& extra_header_value,
+                        content::ResourceType resource_type);
+
+  void ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult result);
+
+  net::TestURLRequestContext* url_request_context() {
+    return test_url_request_context_.get();
+  }
+  Profile* profile() { return profile_; }
+  OfflinePageTabHelper* offline_page_tab_helper() const {
+    return offline_page_tab_helper_;
+  }
+  int64_t offline_id() const { return offline_id_; }
+  int bytes_read() const { return bytes_read_; }
+
+ private:
+  void OnSavePageDone(SavePageResult result, int64_t offline_id);
+  std::unique_ptr<net::URLRequest> CreateRequest(
+      const GURL& url,
+      const std::string& method,
+      content::ResourceType resource_type);
+  void ReadCompleted(int bytes_read);
+
+  // Runs on IO thread.
+  void InterceptRequestOnIO(const GURL& url,
+                            const std::string& method,
+                            const std::string& extra_header_name,
+                            const std::string& extra_header_value,
+                            content::ResourceType resource_type,
+                            void* profile_id);
+  void ReadCompletedOnIO(int bytes_read);
+
+  content::TestBrowserThreadBundle thread_bundle_;
+  std::unique_ptr<TestNetworkChangeNotifier> network_change_notifier_;
+  std::unique_ptr<net::TestURLRequestContext> test_url_request_context_;
+  net::URLRequestJobFactoryImpl url_request_job_factory_;
+  std::unique_ptr<net::URLRequestInterceptingJobFactory>
+      intercepting_job_factory_;
+  std::unique_ptr<TestURLRequestDelegate> url_request_delegate_;
+  net::TestNetworkDelegate network_delegate_;
+  TestingProfileManager profile_manager_;
+  TestingProfile* profile_;
+  std::unique_ptr<content::WebContents> web_contents_;
+  base::HistogramTester histogram_tester_;
+  OfflinePageTabHelper* offline_page_tab_helper_;  // Not owned.
+  std::unique_ptr<net::URLRequest> request_;
+  int64_t offline_id_;
+  int bytes_read_;
+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePageRequestJobTest);
+};
+
+OfflinePageRequestJobTest::OfflinePageRequestJobTest()
+    : thread_bundle_(content::TestBrowserThreadBundle::IO_MAINLOOP),
+      network_change_notifier_(new TestNetworkChangeNotifier()),
+      profile_manager_(TestingBrowserProcess::GetGlobal()),
+      offline_id_(-1),
+      bytes_read_(0)  {
+}
+
+void OfflinePageRequestJobTest::SetUp() {
+  // Create a test profile.
+  ASSERT_TRUE(profile_manager_.SetUp());
+  profile_ = profile_manager_.CreateTestingProfile("Profile 1");
+
+  // Create a test web contents.
+  web_contents_.reset(content::WebContents::Create(
+      content::WebContents::CreateParams(profile_)));
+  OfflinePageTabHelper::CreateForWebContents(web_contents_.get());
+  offline_page_tab_helper_ =
+      OfflinePageTabHelper::FromWebContents(web_contents_.get());
+
+  // Set up the factory for testing.
+  OfflinePageModelFactory::GetInstance()->SetTestingFactoryAndUse(
+      profile(), BuildTestOfflinePageModel);
+  RunUntilIdle();
+
+  // Use a test archive file.
+  base::FilePath archive_file_path;
+  ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &archive_file_path));
+  archive_file_path =
+      archive_file_path.AppendASCII("offline_pages").AppendASCII("test.mhtml");
+  std::unique_ptr<TestOfflinePageArchiver> archiver(
+      new TestOfflinePageArchiver(kTestUrl, archive_file_path));
+
+  // Save an offline page.
+  OfflinePageModel* model =
+      OfflinePageModelFactory::GetForBrowserContext(profile());
+  model->SavePage(
+      kTestUrl, kTestClientId, 0, std::move(archiver),
+      base::Bind(&OfflinePageRequestJobTest::OnSavePageDone,
+                base::Unretained(this)));
+  RunUntilIdle();
+
+  // Create a context with delayed initialization.
+  test_url_request_context_.reset(new net::TestURLRequestContext(true));
+
+  // Install the interceptor.
+  std::unique_ptr<net::URLRequestInterceptor> interceptor(
+      new OfflinePageRequestInterceptor(profile_));
+  std::unique_ptr<net::URLRequestJobFactoryImpl> job_factory_impl(
+      new net::URLRequestJobFactoryImpl());
+  intercepting_job_factory_.reset(new TestURLRequestInterceptingJobFactory(
+      std::move(job_factory_impl),
+      std::move(interceptor),
+      web_contents_.get()));
+
+  test_url_request_context_->set_job_factory(intercepting_job_factory_.get());
+  test_url_request_context_->Init();
+}
+
+void OfflinePageRequestJobTest::SimulateHasNetworkConnectivity(
+    bool online) {
+  network_change_notifier_->set_online(online);
+}
+
+void OfflinePageRequestJobTest::RunUntilIdle() {
+  base::RunLoop().RunUntilIdle();
+}
+
+std::unique_ptr<net::URLRequest> OfflinePageRequestJobTest::CreateRequest(
+    const GURL& url,
+    const std::string& method,
+    content::ResourceType resource_type) {
+  url_request_delegate_ = base::MakeUnique<TestURLRequestDelegate>(
+      base::Bind(&OfflinePageRequestJobTest::ReadCompletedOnIO,
+                 base::Unretained(this)));
+
+  std::unique_ptr<net::URLRequest> request =
+      url_request_context()->CreateRequest(
+          url, net::DEFAULT_PRIORITY, url_request_delegate_.get());
+  request->set_method(method);
+
+  content::ResourceRequestInfo::AllocateForTesting(
+      request.get(),
+      resource_type,
+      nullptr,
+      1,     /* render_process_id */
+      -1,    /* render_view_id */
+      1,     /* render_frame_id */
+      true,  /* is_main_frame */
+      false, /* parent_is_main_frame */
+      true,  /* allow_download */
+      true,  /* is_async */
+      false  /* is_using_lofi */);
+
+  return request;
+}
+
+void OfflinePageRequestJobTest::ExpectAggregatedRequestResultHistogram(
+    OfflinePageRequestJob::AggregatedRequestResult result) {
+  histogram_tester_.ExpectUniqueSample(
+      kAggregatedRequestResultHistogram, static_cast<int>(result), 1);
+}
+
+void OfflinePageRequestJobTest::OnSavePageDone(SavePageResult result,
+                                                   int64_t offline_id) {
+  ASSERT_EQ(SavePageResult::SUCCESS, result);
+  offline_id_ = offline_id;
+}
+
+void OfflinePageRequestJobTest::InterceptRequestOnIO(
+    const GURL& url,
+    const std::string& method,
+    const std::string& extra_header_name,
+    const std::string& extra_header_value,
+    content::ResourceType resource_type,
+    void* profile_id) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  request_ = CreateRequest(url, method, resource_type);
+  if (!extra_header_name.empty()) {
+    request_->SetExtraRequestHeaderByName(
+        extra_header_name, extra_header_value, true);
+  }
+  request_->Start();
+}
+
+void OfflinePageRequestJobTest::InterceptRequest(
+    const GURL& url,
+    const std::string& method,
+    const std::string& extra_header_name,
+    const std::string& extra_header_value,
+    content::ResourceType resource_type) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&OfflinePageRequestJobTest::InterceptRequestOnIO,
+                 base::Unretained(this), url, method, extra_header_name,
+                 extra_header_value, resource_type, profile()));
+}
+
+void OfflinePageRequestJobTest::ReadCompletedOnIO(int bytes_read) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&OfflinePageRequestJobTest::ReadCompleted,
+                 base::Unretained(this), bytes_read));
+}
+
+void OfflinePageRequestJobTest::ReadCompleted(int bytes_read) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  bytes_read_ = bytes_read;
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+}
+
+TEST_F(OfflinePageRequestJobTest, FailedToCreateRequestJob) {
+  SimulateHasNetworkConnectivity(false);
+
+  // Must be http/https URL.
+  InterceptRequest(GURL("ftp://host/doc"), "GET", "", "",
+      content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+
+  InterceptRequest(GURL("file:///path/doc"), "GET", "", "",
+      content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+
+  // Must be GET method.
+  InterceptRequest(
+      kTestUrl, "POST", "", "", content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+
+  InterceptRequest(
+      kTestUrl, "HEAD", "", "", content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+
+  // Must be main resource.
+  InterceptRequest(
+      kTestUrl, "POST", "", "", content::RESOURCE_TYPE_SUB_FRAME);
+  base::RunLoop().Run();
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+
+  InterceptRequest(
+      kTestUrl, "POST", "", "", content::RESOURCE_TYPE_IMAGE);
+  base::RunLoop().Run();
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+}
+
+TEST_F(OfflinePageRequestJobTest, LoadOfflinePageOnDisconnectedNetwork) {
+  SimulateHasNetworkConnectivity(false);
+
+  InterceptRequest(kTestUrl, "GET", "", "", content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(kTestFileSize, bytes_read());
+  ASSERT_TRUE(offline_page_tab_helper()->offline_page());
+  EXPECT_EQ(offline_id(),
+            offline_page_tab_helper()->offline_page()->offline_id);
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          SHOW_OFFLINE_ON_DISCONNECTED_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, PageNotFoundOnDisconnectedNetwork) {
+  SimulateHasNetworkConnectivity(false);
+
+  InterceptRequest(kTestUrl2, "GET", "", "", content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          PAGE_NOT_FOUND_ON_DISCONNECTED_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, LoadOfflinePageOnProhibitivelySlowNetwork) {
+  SimulateHasNetworkConnectivity(true);
+
+  ScopedEnableProbihibitivelySlowNetwork scoped(url_request_context());
+
+  InterceptRequest(kTestUrl, "GET", "", "", content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(kTestFileSize, bytes_read());
+  ASSERT_TRUE(offline_page_tab_helper()->offline_page());
+  EXPECT_EQ(offline_id(),
+            offline_page_tab_helper()->offline_page()->offline_id);
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          SHOW_OFFLINE_ON_PROHIBITIVELY_SLOW_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, PageNotFoundOnProhibitivelySlowNetwork) {
+  SimulateHasNetworkConnectivity(true);
+
+  ScopedEnableProbihibitivelySlowNetwork scoped(url_request_context());
+
+  InterceptRequest(kTestUrl2, "GET", "", "", content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          PAGE_NOT_FOUND_ON_PROHIBITIVELY_SLOW_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, LoadOfflinePageOnFlakyNetwork) {
+  SimulateHasNetworkConnectivity(true);
+
+  // When custom offline header exists and contains "reason=error", it means
+  // that net error is hit in last request due to flaky network.
+  InterceptRequest(
+      kTestUrl,
+      "GET",
+      kLoadingOfflinePageHeader,
+      std::string(kLoadingOfflinePageReason) + kLoadingOfflinePageDueToNetError,
+      content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(kTestFileSize, bytes_read());
+  ASSERT_TRUE(offline_page_tab_helper()->offline_page());
+  EXPECT_EQ(offline_id(),
+            offline_page_tab_helper()->offline_page()->offline_id);
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          SHOW_OFFLINE_ON_FLAKY_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, PageNotFoundOnFlakyNetwork) {
+  SimulateHasNetworkConnectivity(true);
+
+  // When custom offline header exists and contains "reason=error", it means
+  // that net error is hit in last request due to flaky network.
+  InterceptRequest(
+      kTestUrl2,
+      "GET",
+      kLoadingOfflinePageHeader,
+      std::string(kLoadingOfflinePageReason) + kLoadingOfflinePageDueToNetError,
+      content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          PAGE_NOT_FOUND_ON_FLAKY_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, ForceLoadOfflinePageOnConnectedNetwork) {
+  SimulateHasNetworkConnectivity(true);
+
+  // When custom offline header exists and contains value other than
+  // "reason=error", it means that offline page is forced to load.
+  InterceptRequest(
+      kTestUrl,
+      "GET",
+      kLoadingOfflinePageHeader,
+      std::string(kLoadingOfflinePageReason) + "download",
+      content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(kTestFileSize, bytes_read());
+  ASSERT_TRUE(offline_page_tab_helper()->offline_page());
+  EXPECT_EQ(offline_id(),
+            offline_page_tab_helper()->offline_page()->offline_id);
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          SHOW_OFFLINE_ON_CONNECTED_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, PageNotFoundOnConnectedNetwork) {
+  SimulateHasNetworkConnectivity(true);
+
+  // When custom offline header exists and contains value other than
+  // "reason=error", it means that offline page is forced to load.
+  InterceptRequest(
+      kTestUrl2,
+      "GET",
+      kLoadingOfflinePageHeader,
+      std::string(kLoadingOfflinePageReason) + "download",
+      content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+  ExpectAggregatedRequestResultHistogram(
+      OfflinePageRequestJob::AggregatedRequestResult::
+          PAGE_NOT_FOUND_ON_CONNECTED_NETWORK);
+}
+
+TEST_F(OfflinePageRequestJobTest, DoNotLoadOfflinePageOnConnectedNetwork) {
+  SimulateHasNetworkConnectivity(true);
+
+  InterceptRequest(kTestUrl, "GET", "", "", content::RESOURCE_TYPE_MAIN_FRAME);
+  base::RunLoop().Run();
+
+  EXPECT_EQ(0, bytes_read());
+  EXPECT_FALSE(offline_page_tab_helper()->offline_page());
+}
+
+}  // namespace offline_pages