If replacing a safebrowsing interstitial, don't call DontProceed on the old one.

chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc

 // Copyright (c) 2012 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.
 //
 // This test creates a fake safebrowsing service, where we can inject known-
 // threat urls.  It then uses a real browser to go to these urls, and sends
 // "goback" or "proceed" commands and verifies they work.
 
 #include <algorithm>
 
@@ skipping 898 matching lines @@
 IN_PROC_BROWSER_TEST_P(SafeBrowsingBlockingPageBrowserTest,
                        ReportingDisabledByPolicy) {
   SetExtendedReportingPref(browser()->profile()->GetPrefs(), true);
   browser()->profile()->GetPrefs()->SetBoolean(
       prefs::kSafeBrowsingExtendedReportingOptInAllowed, false);
 
   TestReportingDisabledAndDontProceed(
       net::URLRequestMockHTTPJob::GetMockUrl(kEmptyPage));
 }
 
+// Verifies that the reporting checkbox is still shown if the page is reloaded
+// while the interstitial is showing.
+IN_PROC_BROWSER_TEST_P(SafeBrowsingBlockingPageBrowserTest,
+                       ReloadWhileInterstitialShowing) {
+  // Start navigation to bad page (kEmptyPage), which will be blocked before it
+  // is committed.
+  GURL url = SetupWarningAndNavigate();

[meacer, 2016/11/30 00:04:09]

nit: const?

[mattm, 2016/11/30 00:47:41]

Done.

+
+  // Checkbox should be showing.
+  EXPECT_EQ(VISIBLE, GetVisibility("extended-reporting-opt-in"));
+
+  WebContents* tab = browser()->tab_strip_model()->GetActiveWebContents();
+  ASSERT_TRUE(tab);
+  // Security indicator should be showing.
+  ExpectSecurityIndicatorDowngrade(tab, 0u);
+
+  // Check navigation entry state.
+  NavigationController& controller = tab->GetController();

[meacer, 2016/11/30 00:04:09]

const

[mattm, 2016/11/30 00:47:41]

Done.

+  ASSERT_TRUE(controller.GetVisibleEntry());
+  EXPECT_EQ(controller.GetVisibleEntry()->GetURL(), url);

[meacer, 2016/11/30 00:04:09]

nit: The order of params seems reversed here. url is the expected value, so it
should come first. Same below.

[mattm, 2016/11/30 00:47:41]

Done.

+  ASSERT_TRUE(controller.GetPendingEntry());
+  EXPECT_EQ(controller.GetPendingEntry()->GetURL(), url);
+
+  // "Reload" the tab.
+  SetupWarningAndNavigate();
+
+  // Checkbox should be showing.
+  EXPECT_EQ(VISIBLE, GetVisibility("extended-reporting-opt-in"));
+
+  // TODO(crbug.com/666172): Security indicator should be showing.
+  // ExpectSecurityIndicatorDowngrade(tab, 0u);

[meacer, 2016/11/30 00:04:09]

Is this intentionally commented out? If so, you might want to point that out.
E.g. 

// Call |ExpectSecurityIndicatorDowngrade(tab, 0u);| here once the bug is fixed.

[mattm, 2016/11/30 00:47:41]

Done.

+
+  // Check navigation entry state.
+  ASSERT_TRUE(controller.GetVisibleEntry());
+  EXPECT_EQ(controller.GetVisibleEntry()->GetURL(), url);
+  ASSERT_TRUE(controller.GetPendingEntry());
+  EXPECT_EQ(controller.GetPendingEntry()->GetURL(), url);
+}
+
 IN_PROC_BROWSER_TEST_P(SafeBrowsingBlockingPageBrowserTest, LearnMore) {
   SetupWarningAndNavigate();
   EXPECT_TRUE(ClickAndWaitForDetach("learn-more-link"));
   AssertNoInterstitial(false);  // Assert the interstitial is gone
 
   // We are in the help page.
   EXPECT_EQ(
       GURL("https://support.google.com/chrome/answer/99020").GetWithEmptyPath(),
       browser()
           ->tab_strip_model()
@@ skipping 379 matching lines @@
 
 INSTANTIATE_TEST_CASE_P(
     SafeBrowsingBlockingPageIDNTestWithThreatType,
     SafeBrowsingBlockingPageIDNTest,
     testing::Combine(testing::Values(false, true),
                      testing::Values(SB_THREAT_TYPE_URL_MALWARE,
                                      SB_THREAT_TYPE_URL_PHISHING,
                                      SB_THREAT_TYPE_URL_UNWANTED)));
 
 }  // namespace safe_browsing