Clean up defensive TabManager handling

chrome/browser/memory/tab_manager_browsertest.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.
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 30 matching lines @@
 #if !defined(OS_LINUX)
     command_line->AppendSwitchASCII(switches::kEnableFeatures,
                                     features::kAutomaticTabDiscarding.name);
 #endif
   }
 };
 
 IN_PROC_BROWSER_TEST_F(TabManagerTest, TabManagerBasics) {
   using content::WindowedNotificationObserver;
   TabManager* tab_manager = g_browser_process->GetTabManager();
-  ASSERT_TRUE(tab_manager);
   EXPECT_FALSE(tab_manager->recent_tab_discard());
 
   // Disable the protection of recent tabs.
   tab_manager->minimum_protection_time_ = base::TimeDelta::FromMinutes(0);
 
   // Get three tabs open.
   WindowedNotificationObserver load1(
       content::NOTIFICATION_NAV_ENTRY_COMMITTED,
       content::NotificationService::AllSources());
   OpenURLParams open1(GURL(chrome::kChromeUIAboutURL), content::Referrer(),
@@ skipping 119 matching lines @@
   EXPECT_TRUE(chrome::CanGoForward(browser()));
 }
 
 // On Linux, memory pressure listener is not implemented yet.
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_CHROMEOS)
 
 // Test that the MemoryPressureListener event is properly triggering a tab
 // discard upon |MEMORY_PRESSURE_LEVEL_CRITICAL| event.
 IN_PROC_BROWSER_TEST_F(TabManagerTest, OomPressureListener) {
   TabManager* tab_manager = g_browser_process->GetTabManager();
-  ASSERT_TRUE(tab_manager);
 
   // Disable the protection of recent tabs.
   tab_manager->minimum_protection_time_ = base::TimeDelta::FromMinutes(0);
 
   // Get three tabs open.
   content::WindowedNotificationObserver load1(
       content::NOTIFICATION_NAV_ENTRY_COMMITTED,
       content::NotificationService::AllSources());
   OpenURLParams open1(GURL(chrome::kChromeUIAboutURL), content::Referrer(),
                       CURRENT_TAB, ui::PAGE_TRANSITION_TYPED, false);
@@ skipping 29 matching lines @@
     if (tab_manager->recent_tab_discard())
       break;
   }
   EXPECT_TRUE(tab_manager->recent_tab_discard());
 }
 
 #endif
 
 IN_PROC_BROWSER_TEST_F(TabManagerTest, InvalidOrEmptyURL) {
   TabManager* tab_manager = g_browser_process->GetTabManager();
-  ASSERT_TRUE(tab_manager);
 
   // Disable the protection of recent tabs.
   tab_manager->minimum_protection_time_ = base::TimeDelta::FromMinutes(0);
 
   // Open two tabs. Wait for the foreground one to load but do not wait for the
   // background one.
   content::WindowedNotificationObserver load1(
       content::NOTIFICATION_NAV_ENTRY_COMMITTED,
       content::NotificationService::AllSources());
   OpenURLParams open1(GURL(chrome::kChromeUIAboutURL), content::Referrer(),
@@ skipping 15 matching lines @@
   EXPECT_FALSE(tab_manager->DiscardTabImpl());
 
   // Wait for the background tab to load which then allows it to be discarded.
   load2.Wait();
   EXPECT_TRUE(tab_manager->DiscardTabImpl());
 }
 
 // Makes sure that PDF pages are protected.
 IN_PROC_BROWSER_TEST_F(TabManagerTest, ProtectPDFPages) {
   TabManager* tab_manager = g_browser_process->GetTabManager();
-  ASSERT_TRUE(tab_manager);
 
   // Start the embedded test server so we can get served the required PDF page.
   ASSERT_TRUE(embedded_test_server()->InitializeAndListen());
   embedded_test_server()->StartAcceptingConnections();
 
   // Get two tabs open, the first one being a PDF page and the second one being
   // the foreground tab.
   GURL url1 = embedded_test_server()->GetURL("/pdf/test.pdf");
   ui_test_utils::NavigateToURL(browser(), url1);
 
   GURL url2(chrome::kChromeUIAboutURL);
   ui_test_utils::NavigateToURLWithDisposition(
       browser(), url2, NEW_FOREGROUND_TAB,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
 
   // No discarding should be possible as the only background tab is displaying a
   // PDF page, hence protected.
   EXPECT_FALSE(tab_manager->DiscardTabImpl());
 }
 
 // Makes sure that recently opened or used tabs are protected, depending on the
 // value of of |minimum_protection_time_|.
 // TODO(georgesak): Move this to a unit test instead (requires change to API).
 IN_PROC_BROWSER_TEST_F(TabManagerTest, ProtectRecentlyUsedTabs) {
   // TODO(georgesak): Retrieve this value from tab_manager.h once it becomes a
   // constant (as of now, it gets set through variations).
   const int kProtectionTime = 5;
   TabManager* tab_manager = g_browser_process->GetTabManager();
-  ASSERT_TRUE(tab_manager);
 
   base::SimpleTestTickClock test_clock_;
   tab_manager->set_test_tick_clock(&test_clock_);
 
   auto* tsm = browser()->tab_strip_model();
 
   // Set the minimum time of protection.
   tab_manager->minimum_protection_time_ =
       base::TimeDelta::FromMinutes(kProtectionTime);
 
@@ skipping 33 matching lines @@
   EXPECT_TRUE(tab_manager->DiscardTabImpl());
 
   // This is necessary otherwise the test crashes in
   // WebContentsData::WebContentsDestroyed.
   tsm->CloseAllTabs();
 }
 
 // Makes sure that tabs using media devices are protected.
 IN_PROC_BROWSER_TEST_F(TabManagerTest, ProtectVideoTabs) {
   TabManager* tab_manager = g_browser_process->GetTabManager();
-  ASSERT_TRUE(tab_manager);
 
   // Disable the protection of recent tabs.
   tab_manager->minimum_protection_time_ = base::TimeDelta::FromMinutes(0);
 
   // Open 2 tabs, the second one being in the background.
   ui_test_utils::NavigateToURL(browser(), GURL(chrome::kChromeUIAboutURL));
   ui_test_utils::NavigateToURLWithDisposition(
       browser(), GURL(chrome::kChromeUIAboutURL), NEW_BACKGROUND_TAB,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
 
@@ skipping 58 matching lines @@
   tab_manager->SetTabAutoDiscardableState(tsm->GetWebContentsAt(0), true);
 
   // Now it should be able to discard the tab.
   EXPECT_TRUE(tab_manager->DiscardTabImpl());
   EXPECT_TRUE(tab_manager->IsTabDiscarded(tsm->GetWebContentsAt(0)));
 }
 
 }  // namespace memory
 
 #endif  // OS_WIN || OS_MAXOSX || OS_LINUX