Display DNS probe results.

chrome/browser/net/dns_probe_browsertest.cc

+// Copyright (c) 2013 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 "base/bind.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
+#include "base/path_service.h"
+#include "base/threading/thread_restrictions.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/google/google_util.h"
+#include "chrome/browser/io_thread.h"
+#include "chrome/browser/net/dns_probe_test_util.h"
+#include "chrome/browser/net/net_error_tab_helper.h"
+#include "chrome/browser/net/url_request_mock_util.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/common/chrome_paths.h"
+#include "chrome/common/net/net_error_info.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/browser_test_utils.h"
+#include "content/test/net/url_request_failed_job.h"
+#include "content/test/net/url_request_mock_http_job.h"
+#include "net/base/net_errors.h"
+#include "net/dns/dns_test_util.h"
+#include "net/url_request/url_request_filter.h"
+#include "net/url_request/url_request_job.h"
+#include "net/url_request/url_request_job_factory.h"
+
+using base::Bind;
+using base::Callback;
+using base::Closure;
+using base::ConstRef;
+using base::FilePath;
+using base::MessageLoop;
+using base::Unretained;
+using chrome_common_net::DnsProbeStatus;
+using content::BrowserThread;
+using content::URLRequestFailedJob;
+using content::URLRequestMockHTTPJob;
+using content::WebContents;
+using google_util::LinkDoctorBaseURL;
+using net::MockDnsClientRule;
+using net::NetworkDelegate;
+using net::URLRequest;
+using net::URLRequestFilter;
+using net::URLRequestJob;
+using net::URLRequestJobFactory;
+using ui_test_utils::NavigateToURL;
+using ui_test_utils::NavigateToURLBlockUntilNavigationsComplete;
+
+namespace chrome_browser_net {
+
+namespace {
+
+class DelayingDnsProbeService : public DnsProbeService {

[mmenke, 2013/06/28 18:06:19]

Think this is worth a comment (Both what it does and why).

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+ public:
+  DelayingDnsProbeService() : DnsProbeService() {}

[mmenke, 2013/06/28 18:06:19]

nit:  " : DnsProbeService()" not needed.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+
+  virtual void ProbeDns(const ProbeCallback& callback) OVERRIDE {
+    DnsProbeService::ProbeDns(Bind(
+        &DelayingDnsProbeService::WouldCallCallback,
+        Unretained(this),
+        callback));
+  }
+
+  void WouldCallCallback(const ProbeCallback& callback,
+                         DnsProbeStatus result) {
+    delayed_callbacks_.push_back(Bind(callback, result));
+  }
+
+  void CallDelayedCallbacks() {

[mmenke, 2013/06/28 18:06:19]

BUG:  We could have an async call to CallCallbacks pending in DnsProbeService.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+    std::vector<Closure> callbacks;
+    callbacks.swap(delayed_callbacks_);
+
+    for (std::vector<Closure>::const_iterator i = callbacks.begin();
+         i != callbacks.end(); ++i) {
+      i->Run();
+    }
+  }
+
+  int delayed_callback_count() const { return delayed_callbacks_.size(); }
+
+ private:
+  std::vector<Closure> delayed_callbacks_;
+};
+
+FilePath GetMockLinkDoctorFilePath() {
+  FilePath root_http;
+  PathService::Get(chrome::DIR_TEST_DATA, &root_http);
+  return root_http.AppendASCII("mock-link-doctor.html");
+}
+
+class BrokenLinkDoctorProtocolHandler
+    : public URLRequestJobFactory::ProtocolHandler {
+ public:
+  explicit BrokenLinkDoctorProtocolHandler(
+      const FilePath& mock_link_doctor_file_path)
+      : mock_link_doctor_file_path_(mock_link_doctor_file_path),
+        net_error_(net::OK) {}
+
+  virtual ~BrokenLinkDoctorProtocolHandler() {}
+
+  virtual URLRequestJob* MaybeCreateJob(
+      URLRequest* request, NetworkDelegate* network_delegate) const OVERRIDE {
+    if (net_error_ != net::OK) {
+      return new URLRequestFailedJob(request, network_delegate, net_error_);
+    } else {
+      return new URLRequestMockHTTPJob(
+          request, network_delegate, mock_link_doctor_file_path_);
+    }
+  }
+
+  void set_net_error(int net_error) { net_error_ = net_error; }
+
+ private:
+  const FilePath mock_link_doctor_file_path_;
+  int net_error_;
+};
+
+class DnsProbeBrowserTestIOThreadHelper {
+ public:
+  DnsProbeBrowserTestIOThreadHelper();
+
+  void SetUpOnIOThread(IOThread* io_thread);
+  void CleanUpOnIOThreadAndDeleteHelper();
+
+  void SetMockDnsClientRules(MockDnsClientRule::Result system_good_result,
+                             MockDnsClientRule::Result public_good_result);
+  void SetLinkDoctorNetError(int link_doctor_net_error);
+  void CallDelayedProbeCallbacks(int expected_delayed_callback_count);
+
+ private:
+  IOThread* io_thread_;
+  DnsProbeService* original_dns_probe_service_;
+  DelayingDnsProbeService* delaying_dns_probe_service_;
+  BrokenLinkDoctorProtocolHandler* protocol_handler_;
+  FilePath mock_link_doctor_file_path_;
+};
+
+DnsProbeBrowserTestIOThreadHelper::DnsProbeBrowserTestIOThreadHelper()
+    : io_thread_(NULL),
+      original_dns_probe_service_(NULL),
+      delaying_dns_probe_service_(NULL),
+      protocol_handler_(NULL),
+      mock_link_doctor_file_path_(GetMockLinkDoctorFilePath()) {}
+
+void DnsProbeBrowserTestIOThreadHelper::SetUpOnIOThread(IOThread* io_thread) {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  CHECK(io_thread);
+  CHECK(!io_thread_);
+  CHECK(!original_dns_probe_service_);
+  CHECK(!delaying_dns_probe_service_);
+  CHECK(!protocol_handler_);
+
+  io_thread_ = io_thread;
+
+  delaying_dns_probe_service_ = new DelayingDnsProbeService();
+
+  IOThread::Globals* globals = io_thread_->globals();
+  original_dns_probe_service_ = globals->dns_probe_service.release();
+  globals->dns_probe_service.reset(delaying_dns_probe_service_);
+
+  URLRequestFailedJob::AddUrlHandler();
+
+  scoped_ptr<URLRequestJobFactory::ProtocolHandler> protocol_handler(
+      new BrokenLinkDoctorProtocolHandler(mock_link_doctor_file_path_));
+  protocol_handler_ =
+      static_cast<BrokenLinkDoctorProtocolHandler*>(protocol_handler.get());
+  const GURL link_doctor_base_url = LinkDoctorBaseURL();
+  const std::string link_doctor_host = link_doctor_base_url.host();
+  URLRequestFilter::GetInstance()->AddHostnameProtocolHandler(
+      "http", link_doctor_host, protocol_handler.Pass());
+

[mmenke, 2013/06/28 18:06:19]

nit:  Remove blank line.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+}
+
+void DnsProbeBrowserTestIOThreadHelper::CleanUpOnIOThreadAndDeleteHelper() {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  URLRequestFilter::GetInstance()->ClearHandlers();
+
+  DnsProbeService* delaying_dns_probe_service;
+
+  IOThread::Globals* globals = io_thread_->globals();

[mmenke, 2013/06/28 18:06:19]

optional:  Feels safest to me to just always keep the probe in a scoped_ptr.

scoped_ptr<DnsProbeService>
delaying_dns_probe_service(globals->dns_probe_service.release());

Generally feel like we should avoid calling delete, in favor of just always
having someone own an object explicitly (The "delete this" below is fine).

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+  delaying_dns_probe_service = globals->dns_probe_service.release();
+  globals->dns_probe_service.reset(original_dns_probe_service_);
+
+  CHECK_EQ(delaying_dns_probe_service_, delaying_dns_probe_service);
+  delete delaying_dns_probe_service_;
+
+  delete this;
+}
+
+void DnsProbeBrowserTestIOThreadHelper::SetMockDnsClientRules(
+    MockDnsClientRule::Result system_result,
+    MockDnsClientRule::Result public_result) {

[mmenke, 2013/06/28 18:06:19]

CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));?

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+  DnsProbeService* service = io_thread_->globals()->dns_probe_service.get();
+  service->SetSystemClientForTesting(
+      CreateMockDnsClientForProbes(system_result));
+  service->SetPublicClientForTesting(
+      CreateMockDnsClientForProbes(public_result));
+}
+
+void DnsProbeBrowserTestIOThreadHelper::SetLinkDoctorNetError(
+    int link_doctor_net_error) {

[mmenke, 2013/06/28 18:06:19]

CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));?

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+  protocol_handler_->set_net_error(link_doctor_net_error);
+}
+
+void DnsProbeBrowserTestIOThreadHelper::CallDelayedProbeCallbacks(
+    int expected_delayed_callback_count) {

[mmenke, 2013/06/28 18:06:19]

CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));?

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+  CHECK(delaying_dns_probe_service_);
+
+  if (expected_delayed_callback_count >= 0) {

[mmenke, 2013/06/28 18:06:19]

nit:  Is this needed?

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+    int actual_delayed_callback_count =
+        delaying_dns_probe_service_->delayed_callback_count();
+    EXPECT_EQ(expected_delayed_callback_count, actual_delayed_callback_count);
+  }
+
+  delaying_dns_probe_service_->CallDelayedCallbacks();
+}
+
+class DnsProbeBrowserTest : public InProcessBrowserTest {
+ public:
+  DnsProbeBrowserTest();
+
+  virtual void SetUpOnMainThread() OVERRIDE;
+  virtual void CleanUpOnMainThread() OVERRIDE;
+
+ protected:
+  void SetLinkDoctorBroken(bool broken);
+  void SetMockDnsClientRules(MockDnsClientRule::Result system_result,
+                             MockDnsClientRule::Result public_result);
+  void NavigateToDnsError();
+  void NavigateToOtherError();
+
+  void CallDelayedProbeCallbacks(int expected_delayed_callback_count);
+  DnsProbeStatus WaitForSentStatus();
+  int dns_probe_status_count() const { return dns_probe_status_count_; }
+
+  bool TitleIs(const std::string& expected);
+  bool PageContains(const std::string& expected);
+
+ private:
+  void OnDnsProbeStatusSent(DnsProbeStatus dns_probe_status);
+
+  DnsProbeBrowserTestIOThreadHelper* helper_;
+
+  bool awaiting_dns_probe_status_;
+  int dns_probe_status_count_;
+  std::list<DnsProbeStatus> dns_probe_statuses_;
+};
+
+DnsProbeBrowserTest::DnsProbeBrowserTest()
+    : helper_(new DnsProbeBrowserTestIOThreadHelper()),
+      awaiting_dns_probe_status_(false),
+      dns_probe_status_count_(0) {
+}
+
+void DnsProbeBrowserTest::SetUpOnMainThread() {
+  NetErrorTabHelper::set_state_for_testing(
+      NetErrorTabHelper::TESTING_FORCE_ENABLED);
+
+  CHECK(helper_);

[mmenke, 2013/06/28 18:06:19]

optional:  This seems like overkill, since we never set it to NULL (Same goes
for the same check in the next function).

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      Bind(&DnsProbeBrowserTestIOThreadHelper::SetUpOnIOThread,
+           Unretained(helper_),
+           g_browser_process->io_thread()));
+
+  NetErrorTabHelper* tab_helper = NetErrorTabHelper::FromWebContents(
+      browser()->tab_strip_model()->GetActiveWebContents());
+  tab_helper->set_dns_probe_status_snoop_callback_for_testing(Bind(
+      &DnsProbeBrowserTest::OnDnsProbeStatusSent,
+      Unretained(this)));
+}
+
+void DnsProbeBrowserTest::CleanUpOnMainThread() {
+  CHECK(helper_);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      Bind(&DnsProbeBrowserTestIOThreadHelper::CleanUpOnIOThreadAndDeleteHelper,
+           Unretained(helper_)));
+
+  NetErrorTabHelper::set_state_for_testing(
+      NetErrorTabHelper::TESTING_DEFAULT);
+}
+
+void DnsProbeBrowserTest::SetLinkDoctorBroken(bool broken) {
+  int net_error = broken ? net::ERR_NAME_NOT_RESOLVED : net::OK;
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      Bind(&DnsProbeBrowserTestIOThreadHelper::SetLinkDoctorNetError,
+           Unretained(helper_),
+           net_error));
+}
+
+// These two functions wait for two navigations because Link Doctor loads two
+// pages: a blank page, so the user stops seeing the previous page, and then
+// either the Link Doctor page or a regular error page.  We want to wait for
+// the error page, so we wait for both loads to finish.
+
+void DnsProbeBrowserTest::NavigateToDnsError() {
+  NavigateToURLBlockUntilNavigationsComplete(
+      browser(),
+      URLRequestFailedJob::GetMockHttpUrl(net::ERR_NAME_NOT_RESOLVED),
+      2);
+}
+
+void DnsProbeBrowserTest::NavigateToOtherError() {
+  NavigateToURLBlockUntilNavigationsComplete(
+      browser(),
+      URLRequestFailedJob::GetMockHttpUrl(net::ERR_CONNECTION_REFUSED),
+      2);
+}

[mmenke, 2013/06/28 18:06:19]

Hmm...Worth the effort of a test with link doctor disabled?  Disabling the link
doctor does disable the DNS probe...  unless the link doctor is disabled due to
lack of API keys.  Don't intend to delay the CL on this, and may not even be
worth doing at all, but thought I'd bring it up.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Not in this CL, but sure.

+
+void DnsProbeBrowserTest::SetMockDnsClientRules(
+    MockDnsClientRule::Result system_result,
+    MockDnsClientRule::Result public_result) {
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      Bind(&DnsProbeBrowserTestIOThreadHelper::SetMockDnsClientRules,
+           Unretained(helper_),
+           system_result,
+           public_result));
+}
+
+void DnsProbeBrowserTest::CallDelayedProbeCallbacks(
+    int expected_delayed_callback_count) {
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      Bind(&DnsProbeBrowserTestIOThreadHelper::CallDelayedProbeCallbacks,
+           Unretained(helper_),
+           expected_delayed_callback_count));
+}
+
+DnsProbeStatus DnsProbeBrowserTest::WaitForSentStatus() {
+  CHECK(!awaiting_dns_probe_status_);
+  while (dns_probe_statuses_.empty()) {
+    awaiting_dns_probe_status_ = true;
+    MessageLoop::current()->Run();

[mmenke, 2013/06/28 18:06:19]

RunLoop is now "right" way of doing this.

I believe in cases like this, the correct way to use the RunLoop is for the
DnsProbeBrowserTest to have a RunLoop as a member variable, and to exit the loop
by calling the RunLoop's Quit function (This makes nested message loops safe. 
Of course, since 99% of browser tests still use MessageLoops, or incorrectly use
RunLoops, doesn't actually work, but....)

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

I think I am doing something wrong; I tried sticking a RunLoop in the class and
it segfaulted (!) when I called Run.  (The same thing happened when I did
RunLoop().Run() directly.)

Can we look at this on Monday?

[mmenke, 2013/07/01 18:11:44]

Sorry, I thought I'd told you, I'm taking a week off.  I'll be back on the 10th
(Next Wednesday).

+    awaiting_dns_probe_status_ = false;
+  }
+
+  CHECK(!dns_probe_statuses_.empty());
+  DnsProbeStatus status = dns_probe_statuses_.front();
+  dns_probe_statuses_.pop_front();
+  return status;
+}
+
+// Check title by roundtripping to renderer, to make sure any probe results
+// sent before this have been applied.
+bool DnsProbeBrowserTest::TitleIs(const std::string& expected) {

[mmenke, 2013/06/28 18:06:19]

Suggest making this return the title instead of a bool.  Then can use EXPECT_EQ,
and get useful output on failure.

Doesn't apply to next function, of course.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+  std::string title;
+
+  WebContents* contents =
+      browser()->tab_strip_model()->GetActiveWebContents();
+
+  bool rv = content::ExecuteScriptAndExtractString(
+      contents,
+      "domAutomationController.send(document.title);",
+      &title);
+  if (!rv)
+    return false;
+
+  return title == expected;
+}
+
+// Check text by roundtripping to renderer, to make sure any probe results
+// sent before this have been applied.
+bool DnsProbeBrowserTest::PageContains(const std::string& expected) {
+  std::string text_content;
+
+  bool rv = content::ExecuteScriptAndExtractString(
+      browser()->tab_strip_model()->GetActiveWebContents(),
+      "domAutomationController.send(document.body.textContent);",
+      &text_content);
+  if (!rv)
+    return false;
+
+  return text_content.find(expected) != std::string::npos;
+}
+
+void DnsProbeBrowserTest::OnDnsProbeStatusSent(
+    DnsProbeStatus dns_probe_status) {
+  dns_probe_statuses_.push_back(dns_probe_status);
+
+  dns_probe_status_count_++;
+  if (awaiting_dns_probe_status_)
+    MessageLoop::current()->Quit();
+}
+
+IN_PROC_BROWSER_TEST_F(DnsProbeBrowserTest, OtherErrorWithLinkDoctor) {
+  SetLinkDoctorBroken(false);
+
+  NavigateToOtherError();
+  EXPECT_TRUE(TitleIs("Mock Link Doctor"));
+
+  EXPECT_EQ(0, dns_probe_status_count());

[mmenke, 2013/06/28 18:06:19]

Should we do something like "CallDelayedProbeCallbacks(0);"?  Admittedly, if
something goes wrong, we should still send PROBE_STARTED message, but can be a
bit more aggressive now as well.

Alternatively, on destruction, can have the DelayedProbeThing EXPECT that it has
no probes pending (Don't think CHECK is needed there, since we won't hang
because of something going wrong there).  This is probably the better option,
since it adds an extra check to all tests.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+}
+
+IN_PROC_BROWSER_TEST_F(DnsProbeBrowserTest, OtherErrorWithoutLinkDoctor) {

[mmenke, 2013/06/28 18:06:19]

Do we care about an error page that doesn't try to use the link doctor?  I don't
think we do, as there's no relevant difference there.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

This is mostly here to ensure that GetErrorStringForDnsProbe isn't erroneously
returning true and mangling all error pages.

+  SetLinkDoctorBroken(true);
+
+  NavigateToOtherError();
+  EXPECT_TRUE(PageContains("CONNECTION_REFUSED"));
+
+  EXPECT_EQ(0, dns_probe_status_count());
+}
+
+IN_PROC_BROWSER_TEST_F(DnsProbeBrowserTest, NxdomainWithLinkDoctor) {

[mmenke, 2013/06/28 18:06:19]

Suggest a comment describing what this particular test tests.  I just think
naming it Nxdomain when the mock DNS returns a valid address is a little
confusing, though I don't disagree with the test name.  Other tests are fine.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+  SetLinkDoctorBroken(false);
+  SetMockDnsClientRules(MockDnsClientRule::OK, MockDnsClientRule::OK);
+
+  NavigateToDnsError();
+  EXPECT_TRUE(TitleIs("Mock Link Doctor"));

[mmenke, 2013/06/28 18:06:19]

We run probes and send messages here, think we should probably still let them
all run (Along with the probe) and make sure the title doesn't change.  Can't
see how it would, but paranoia is your friend.

[Deprecated (see juliatuttle), 2013/07/01 17:39:55]

Done.

+}
+
+IN_PROC_BROWSER_TEST_F(DnsProbeBrowserTest, NoInternetWithoutLinkDoctor) {
+  SetLinkDoctorBroken(true);
+  SetMockDnsClientRules(MockDnsClientRule::TIMEOUT,
+                        MockDnsClientRule::TIMEOUT);
+
+  NavigateToDnsError();
+
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_STARTED, WaitForSentStatus());
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_STARTED, WaitForSentStatus());
+
+  // PageContains runs the RunLoop, so make sure nothing hairy happens.
+  EXPECT_EQ(2, dns_probe_status_count());
+  EXPECT_TRUE(PageContains("DNS_PROBE_STARTED"));
+  EXPECT_EQ(2, dns_probe_status_count());
+
+  CallDelayedProbeCallbacks(1);
+
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_FINISHED_NO_INTERNET,
+            WaitForSentStatus());
+
+  // PageContains runs the RunLoop, so make sure nothing hairy happens.
+  EXPECT_EQ(3, dns_probe_status_count());
+  EXPECT_TRUE(PageContains("DNS_PROBE_FINISHED_NO_INTERNET"));
+  EXPECT_EQ(3, dns_probe_status_count());
+}
+
+IN_PROC_BROWSER_TEST_F(DnsProbeBrowserTest, SyncFailureWithoutLinkDoctor) {
+  SetLinkDoctorBroken(true);
+  SetMockDnsClientRules(MockDnsClientRule::FAIL_SYNC,
+                        MockDnsClientRule::FAIL_SYNC);
+
+  NavigateToDnsError();
+
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_STARTED, WaitForSentStatus());
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_STARTED, WaitForSentStatus());
+
+  // PageContains runs the RunLoop, so make sure nothing hairy happens.
+  EXPECT_EQ(2, dns_probe_status_count());
+  EXPECT_TRUE(PageContains("DNS_PROBE_STARTED"));
+  EXPECT_EQ(2, dns_probe_status_count());
+
+  CallDelayedProbeCallbacks(1);
+
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_FINISHED_UNKNOWN,
+            WaitForSentStatus());
+
+  // PageContains runs the RunLoop, so make sure nothing hairy happens.
+  EXPECT_EQ(3, dns_probe_status_count());
+  EXPECT_TRUE(PageContains("NAME_NOT_RESOLVED"));
+  EXPECT_EQ(3, dns_probe_status_count());
+}
+
+IN_PROC_BROWSER_TEST_F(DnsProbeBrowserTest, NoProbeInSubframe) {
+  SetLinkDoctorBroken(false);
+
+  const FilePath::CharType kIframeDnsErrorHtmlName[] =
+      FILE_PATH_LITERAL("iframe_dns_error.html");
+
+  NavigateToURL(
+      browser(),
+      URLRequestMockHTTPJob::GetMockUrl(FilePath(kIframeDnsErrorHtmlName)));
+
+  // By the time NavigateToURL returns, the browser will have seen the failed
+  // provisional load.  If a probe was started (or considered but not run),
+  // then the NetErrorTabHelper would have sent a NetErrorInfo message.  Thus,
+  // if one hasn't been sent by now, the NetErrorTabHelper has not (and won't)
+  // start a probe for this DNS error.
+  EXPECT_EQ(0, dns_probe_status_count());
+}
+
+IN_PROC_BROWSER_TEST_F(DnsProbeBrowserTest, ProbesDisabled) {
+  NetErrorTabHelper::set_state_for_testing(
+      NetErrorTabHelper::TESTING_FORCE_DISABLED);
+
+  SetLinkDoctorBroken(true);
+  SetMockDnsClientRules(MockDnsClientRule::TIMEOUT,
+                        MockDnsClientRule::TIMEOUT);
+
+  NavigateToDnsError();
+
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_NOT_RUN, WaitForSentStatus());
+  EXPECT_EQ(chrome_common_net::DNS_PROBE_NOT_RUN, WaitForSentStatus());
+
+  // PageContains runs the RunLoop, so make sure nothing hairy happens.
+  EXPECT_EQ(2, dns_probe_status_count());
+  EXPECT_TRUE(PageContains("NAME_NOT_RESOLVED"));
+  EXPECT_EQ(2, dns_probe_status_count());
+}
+
+}  // namespace
+
+}  // namespace chrome_browser_net