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

chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc

Index: chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc
index ac689e669aed028fbbe2d38dd04560cc2968580e..5bed346295e63c828413fbe7def0e53d8c8ac90c 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc
@@ -916,6 +916,45 @@ IN_PROC_BROWSER_TEST_P(SafeBrowsingBlockingPageBrowserTest,
       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"));