Avoid showing the supervised user block interstitial more than once

chrome/browser/supervised_user/supervised_user_navigation_throttle_browsertest.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 <memory>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/memory/ptr_util.h"
 #include "base/path_service.h"
@@ skipping 55 matching lines @@
   host_resolver()->AddIPLiteralRule("*", "127.0.0.1", "localhost");
 
   ASSERT_TRUE(embedded_test_server()->Start());
 }
 
 void SupervisedUserNavigationThrottleTest::SetUpCommandLine(
     base::CommandLine* command_line) {
   command_line->AppendSwitchASCII(switches::kSupervisedUserId, "asdf");
 }
 
-// Tests that showing the blocking interstitial for a WebContents without a
-// SupervisedUserNavigationObserver doesn't crash.
+// Tests that navigating to a blocked page simply fails if there is no
+// SupervisedUserNavigationObserver.
 IN_PROC_BROWSER_TEST_F(SupervisedUserNavigationThrottleTest,
                        NoNavigationObserverBlock) {
   Profile* profile = browser()->profile();
   SupervisedUserSettingsService* supervised_user_settings_service =
       SupervisedUserSettingsServiceFactory::GetForProfile(profile);
   supervised_user_settings_service->SetLocalSetting(
       supervised_users::kContentPackDefaultFilteringBehavior,
       std::unique_ptr<base::Value>(
           new base::Value(SupervisedUserURLFilter::BLOCK)));
 
   std::unique_ptr<WebContents> web_contents(
       WebContents::Create(WebContents::CreateParams(profile)));
   NavigationController& controller = web_contents->GetController();
   content::TestNavigationObserver observer(web_contents.get());
   controller.LoadURL(GURL("http://www.example.com"), content::Referrer(),
                      ui::PAGE_TRANSITION_TYPED, std::string());
   observer.Wait();
   content::NavigationEntry* entry = controller.GetActiveEntry();
   ASSERT_TRUE(entry);
-  EXPECT_EQ(content::PAGE_TYPE_INTERSTITIAL, entry->GetPageType());
+  EXPECT_EQ(content::PAGE_TYPE_NORMAL, entry->GetPageType());
+  EXPECT_FALSE(observer.last_navigation_succeeded());
 }
 
 IN_PROC_BROWSER_TEST_F(SupervisedUserNavigationThrottleTest,
                        BlockMainFrameWithInterstitial) {
   BlockHost(kExampleHost2);
 
   WebContents* tab = browser()->tab_strip_model()->GetActiveWebContents();
 
   GURL allowed_url = embedded_test_server()->GetURL(
       kExampleHost, "/supervised_user/simple.html");
@@ skipping 46 matching lines @@
 
   WebContents* tab = browser()->tab_strip_model()->GetActiveWebContents();
 
   GURL blocked_url = embedded_test_server()->GetURL(
       kExampleHost, "/supervised_user/simple.html");
   ui_test_utils::NavigateToURL(browser(), blocked_url);
   // Even though the URL is marked as blocked, the load should go through, since
   // the user isn't supervised.
   EXPECT_FALSE(tab->ShowingInterstitialPage());
 }