Defer loading internal pages for background tabs

Internal pages are deferred to load after other pages.

Bug: 730098
Change-Id: I3b8f2dbbb1d7e2e4d858750432597e882ef60b9f
Reviewed-on: https://chromium-review.googlesource.com/585241
Commit-Queue: Zhen Wang <zhenw@chromium.org>
Reviewed-by: Chris Hamilton <chrisha@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490710}

chrome/browser/resource_coordinator/tab_manager.cc

@@ -1118,6 +1118,8 @@ TabManager::MaybeThrottleNavigation(BackgroundTabNavigationThrottle* throttle) {
   GetWebContentsData(navigation_handle->GetWebContents())
       ->SetTabLoadingState(TAB_IS_NOT_LOADING);
   pending_navigations_.push_back(throttle);
+  std::stable_sort(pending_navigations_.begin(), pending_navigations_.end(),
+                   ComparePendingNavigations);
 
   StartForceLoadTimer();
   return content::NavigationThrottle::DEFER;
@@ -1211,6 +1213,21 @@ BackgroundTabNavigationThrottle* TabManager::RemovePendingNavigationIfNeeded(
   return nullptr;
 }
 
+// static
+bool TabManager::ComparePendingNavigations(
+    const BackgroundTabNavigationThrottle* first,
+    const BackgroundTabNavigationThrottle* second) {
+  bool first_is_internal_page =
+      IsInternalPage(first->navigation_handle()->GetURL());
+  bool second_is_internal_page =
+      IsInternalPage(second->navigation_handle()->GetURL());
+
+  if (first_is_internal_page != second_is_internal_page)
+    return !first_is_internal_page;
+
+  return false;
+}
+
 bool TabManager::IsTabLoadingForTest(content::WebContents* contents) const {
   if (loading_contents_.count(contents) == 1) {
     DCHECK_EQ(TAB_IS_LOADING,

chrome/browser/resource_coordinator/tab_manager.h

@@ -241,6 +241,7 @@ class TabManager : public TabStripModelObserver,
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, OnDelayedTabSelected);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, TimeoutWhenLoadingBackgroundTabs);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, BackgroundTabLoadingSlots);
+  FRIEND_TEST_ALL_PREFIXES(TabManagerTest, BackgroundTabsLoadingOrdering);
   FRIEND_TEST_ALL_PREFIXES(TabManagerStatsCollectorTest,
                            HistogramsSessionRestoreSwitchToTab);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest,
@@ -426,6 +427,11 @@ class TabManager : public TabStripModelObserver,
   BackgroundTabNavigationThrottle* RemovePendingNavigationIfNeeded(
       content::WebContents* contents);
 
+  // Returns true if |first| is considered to resume navigation before |second|.
+  static bool ComparePendingNavigations(
+      const BackgroundTabNavigationThrottle* first,
+      const BackgroundTabNavigationThrottle* second);
+
   // Check if the tab is loading. Use only in tests.
   bool IsTabLoadingForTest(content::WebContents* contents) const;
 

chrome/browser/resource_coordinator/tab_manager_unittest.cc

@@ -132,22 +132,22 @@ class TabManagerTest : public ChromeRenderViewHostTestHarness {
     return web_contents;
   }
 
-  std::unique_ptr<NavigationHandle> CreateTabAndNavigation() {
+  std::unique_ptr<NavigationHandle> CreateTabAndNavigation(const char* url) {
     content::TestWebContents* web_contents =
         content::TestWebContents::Create(profile(), nullptr);
     return content::NavigationHandle::CreateNavigationHandleForTesting(
-        GURL(kTestUrl), web_contents->GetMainFrame());
-  }
-
-  void MaybeThrottleNavigations(TabManager* tab_manager) {
-    MaybeThrottleNavigations(tab_manager, 1);
+        GURL(url), web_contents->GetMainFrame());
   }
 
   // Simulate creating 3 tabs and their navigations.
-  void MaybeThrottleNavigations(TabManager* tab_manager, size_t loading_slots) {
-    nav_handle1_ = CreateTabAndNavigation();
-    nav_handle2_ = CreateTabAndNavigation();
-    nav_handle3_ = CreateTabAndNavigation();
+  void MaybeThrottleNavigations(TabManager* tab_manager,
+                                size_t loading_slots = 1,
+                                const char* url1 = kTestUrl,
+                                const char* url2 = kTestUrl,
+                                const char* url3 = kTestUrl) {
+    nav_handle1_ = CreateTabAndNavigation(url1);
+    nav_handle2_ = CreateTabAndNavigation(url2);
+    nav_handle3_ = CreateTabAndNavigation(url3);
     contents1_ = nav_handle1_->GetWebContents();
     contents2_ = nav_handle2_->GetWebContents();
     contents3_ = nav_handle3_->GetWebContents();
@@ -875,4 +875,33 @@ TEST_F(TabManagerTest, BackgroundTabLoadingSlots) {
   EXPECT_FALSE(tab_manager3.IsNavigationDelayedForTest(nav_handle3_.get()));
 }
 
+TEST_F(TabManagerTest, BackgroundTabsLoadingOrdering) {
+  TabManager* tab_manager = g_browser_process->GetTabManager();
+  base::SimpleTestTickClock test_clock;
+  tab_manager->set_test_tick_clock(&test_clock);
+
+  MaybeThrottleNavigations(
+      tab_manager, 1, kTestUrl,
+      chrome::kChromeUISettingsURL,  // Using internal page URL for tab 2.
+      kTestUrl);
+  tab_manager->GetWebContentsData(contents1_)
+      ->DidStartNavigation(nav_handle1_.get());
+
+  EXPECT_TRUE(tab_manager->IsTabLoadingForTest(contents1_));
+  EXPECT_FALSE(tab_manager->IsTabLoadingForTest(contents2_));
+  EXPECT_FALSE(tab_manager->IsTabLoadingForTest(contents3_));
+  EXPECT_FALSE(tab_manager->IsNavigationDelayedForTest(nav_handle1_.get()));
+  EXPECT_TRUE(tab_manager->IsNavigationDelayedForTest(nav_handle2_.get()));
+  EXPECT_TRUE(tab_manager->IsNavigationDelayedForTest(nav_handle3_.get()));
+
+  // Simulate tab 1 has finished loading. Tab 3 should be loaded before tab 2,
+  // because tab 2 is internal page.
+  tab_manager->GetWebContentsData(contents1_)->DidStopLoading();
+
+  EXPECT_FALSE(tab_manager->IsTabLoadingForTest(contents2_));
+  EXPECT_TRUE(tab_manager->IsTabLoadingForTest(contents3_));
+  EXPECT_TRUE(tab_manager->IsNavigationDelayedForTest(nav_handle2_.get()));
+  EXPECT_FALSE(tab_manager->IsNavigationDelayedForTest(nav_handle3_.get()));
+}
+
 }  // namespace resource_coordinator