Use TabLoader in TabRestoreService.

chrome/browser/sessions/tab_restore_browsertest.cc

Index: chrome/browser/sessions/tab_restore_browsertest.cc
diff --git a/chrome/browser/sessions/tab_restore_browsertest.cc b/chrome/browser/sessions/tab_restore_browsertest.cc
index b7e444d76ae84f1095dd57728058f957f25d1af3..c0aff3695868ed360e519aaab122c234ffe527ae 100644
--- a/chrome/browser/sessions/tab_restore_browsertest.cc
+++ b/chrome/browser/sessions/tab_restore_browsertest.cc
@@ -17,6 +17,7 @@
 #include "chrome/browser/lifetime/scoped_keep_alive.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/browser/sessions/session_restore_test_helper.h"
+#include "chrome/browser/sessions/tab_loader.h"
 #include "chrome/browser/sessions/tab_restore_service_factory.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_commands.h"
@@ -638,15 +639,16 @@ IN_PROC_BROWSER_TEST_F(TabRestoreTest, RestoreWindow) {
   EXPECT_EQ(initial_tab_count + 2, browser->tab_strip_model()->count());
   load_stop_observer.Wait();
 
+  EXPECT_EQ(initial_tab_count + 1, browser->tab_strip_model()->active_index());
   content::WebContents* restored_tab =
-      browser->tab_strip_model()->GetWebContentsAt(initial_tab_count);
+      browser->tab_strip_model()->GetWebContentsAt(initial_tab_count + 1);
   EnsureTabFinishedRestoring(restored_tab);
-  EXPECT_EQ(url1_, restored_tab->GetURL());
+  EXPECT_EQ(url2_, restored_tab->GetURL());
 
   restored_tab =
-      browser->tab_strip_model()->GetWebContentsAt(initial_tab_count + 1);
+      browser->tab_strip_model()->GetWebContentsAt(initial_tab_count);
   EnsureTabFinishedRestoring(restored_tab);
-  EXPECT_EQ(url2_, restored_tab->GetURL());
+  EXPECT_EQ(url1_, restored_tab->GetURL());
 }
 
 // Restore tab with special URL chrome://credits/ and make sure the page loads
@@ -759,3 +761,50 @@ IN_PROC_BROWSER_TEST_F(TabRestoreTest,
   Browser* browser = GetBrowser(0);
   EXPECT_EQ(4, browser->tab_strip_model()->count());
 }
+
+#if BUILDFLAG(ENABLE_SESSION_SERVICE)

[sky, 2017/03/02 19:12:05]

Why does this require session service?

[Michael K. (Yandex Team), 2017/03/03 08:26:37]

Because of TabLoader: it depends on this buildflag.
See chrome/browser/BUILD.gn ex.

I added a cooment here in the next patchset.

+IN_PROC_BROWSER_TEST_F(TabRestoreTest,
+                       TabsFromRestoredWindowsAreLoadedGradually) {
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), url2_,
+      WindowOpenDisposition::NEW_WINDOW,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_BROWSER);
+  Browser* browser2 = GetBrowser(1);
+
+  // Add tabs and close browser.
+  AddSomeTabs(browser2, 3);
+  EXPECT_EQ(4, browser2->tab_strip_model()->count());

[sky, 2017/03/02 19:12:05]

Use a constant for this so to make it clear the restored tab should have the
same number of tabs created here. Also use that constant in the previous line.

[Michael K. (Yandex Team), 2017/03/03 08:26:37]

Done.

+  content::WindowedNotificationObserver observer(
+      chrome::NOTIFICATION_BROWSER_CLOSED,
+      content::NotificationService::AllSources());
+  chrome::CloseWindow(browser2);
+  observer.Wait();
+
+  // Limit the number of restored tabs that should be loaded.

[sky, 2017/03/02 19:12:05]

'should be' -> 'are'

[Michael K. (Yandex Team), 2017/03/03 08:26:37]

Done.

+  TabLoader::SetMaxLoadedTabCountForTest(2);
+
+  // Restore recently closed window.
+  content::WindowedNotificationObserver open_window_observer(
+      chrome::NOTIFICATION_BROWSER_OPENED,
+      content::NotificationService::AllSources());
+  chrome::OpenWindowWithRestoredTabs(browser()->profile());
+  open_window_observer.Wait();
+  browser2 = GetBrowser(1);
+
+  EXPECT_EQ(4, browser2->tab_strip_model()->count());
+  EXPECT_EQ(3, browser2->tab_strip_model()->active_index());
+  // These two tabs should be loaded by TabLoader.
+  EnsureTabFinishedRestoring(browser2->tab_strip_model()->GetWebContentsAt(3));
+  EnsureTabFinishedRestoring(browser2->tab_strip_model()->GetWebContentsAt(0));
+  // It isn't necessary but just to be sure there is no any async task that

[sky, 2017/03/02 19:12:05]

I don't understand this comment. Can you elaborate on why this is needed?

[Michael K. (Yandex Team), 2017/03/03 08:26:37]

I made small fix here in the next patchset.

What I want to say: The last block (for-cycle) and its expectations can be ok if
we check it immediately. But what if there is an async/pending task that can
break these expectations?
RunAllPendingInMessageLoop adds a bit more reliability that there is no such a
task. That nothing can break these expectations.

Of course the test works without this RunAllPendingInMessageLoop.

+  // could have an impact on the expectations below.
+  content::RunAllPendingInMessageLoop();
+
+  // These tabs shouldn't want to be loaded.
+  for (int tab_idx = 1; tab_idx < 3; ++tab_idx) {
+    auto* contents = browser2->tab_strip_model()->GetWebContentsAt(tab_idx);
+    EXPECT_FALSE(contents->IsLoading());
+    EXPECT_TRUE(contents->GetController().NeedsReload());
+  }
+}
+#endif  // ENABLE_SESSION_SERVICE