[Tab Metrics] Measure FP, FCP and FMP for Foreground Tab during Session Restore

chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

Index: chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc b/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
index 4d5a1ca1253e4e2a14eefbe8af41a381ecaa1253..43f7adee7e6311f03c6f076131b1ed938b4f06b4 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
+++ b/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
@@ -11,16 +11,26 @@
 #include "base/test/histogram_tester.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
+#include "build/build_config.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/lifetime/keep_alive_types.h"
+#include "chrome/browser/lifetime/scoped_keep_alive.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #include "chrome/browser/page_load_metrics/observers/aborts_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/no_state_prefetch_page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/observers/session_restore_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/page_load_tracker.h"
+#include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/browser/prerender/prerender_histograms.h"
 #include "chrome/browser/prerender/prerender_origin.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/sessions/session_service_factory.h"
+#include "chrome/browser/sessions/session_service_test_helper.h"
+#include "chrome/browser/sessions/tab_loader.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/browser_navigator_params.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_features.h"
@@ -34,6 +44,7 @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/common/content_features.h"
 #include "content/public/common/content_switches.h"
+#include "content/public/common/referrer.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/download_test_observer.h"
 #include "net/base/net_errors.h"
@@ -1049,3 +1060,198 @@ IN_PROC_BROWSER_TEST_F(PageLoadMetricsBrowserTest,
 
   histogram_tester_.ExpectUniqueSample(internal::kHistogramTotalBytes, 0, 1);
 }
+
+class SessionRestorePageLoadMetricsBrowserTest
+    : public PageLoadMetricsBrowserTest {
+ public:
+  SessionRestorePageLoadMetricsBrowserTest() {}
+
+  void SetUpOnMainThread() override {
+    PageLoadMetricsBrowserTest::SetUpOnMainThread();
+    SessionStartupPref::SetStartupPref(
+        browser()->profile(), SessionStartupPref(SessionStartupPref::LAST));
+    ASSERT_TRUE(embedded_test_server()->Start());
+#if defined(OS_CHROMEOS)
+    SessionServiceTestHelper helper(
+        SessionServiceFactory::GetForProfile(browser()->profile()));
+    helper.SetForceBrowserNotAliveWithNoWindows(true);
+    helper.ReleaseService();
+#endif
+  }
+
+  Browser* QuitBrowserAndRestore(Browser* browser) {
+    Profile* profile = browser->profile();
+
+    // Close the browser.
+    std::unique_ptr<ScopedKeepAlive> keep_alive(new ScopedKeepAlive(
+        KeepAliveOrigin::SESSION_RESTORE, KeepAliveRestartOption::DISABLED));
+    CloseBrowserSynchronously(browser);
+
+    // Create a new window, which should trigger session restore.
+    chrome::NewEmptyWindow(profile);
+    ui_test_utils::BrowserAddedObserver window_observer;
+    return window_observer.WaitForSingleNewBrowser();
+  }
+
+  std::unique_ptr<PageLoadMetricsWaiter> CreatePageLoadMetricsWaiter(
+      content::WebContents* web_contents) const {
+    return base::MakeUnique<PageLoadMetricsWaiter>(web_contents);
+  }
+
+  void WaitForFirstMeaningfulPaintOfActiveTab(Browser* browser) const {
+    auto waiter = CreatePageLoadMetricsWaiter(
+        browser->tab_strip_model()->GetActiveWebContents());
+    waiter->AddPageExpectation(TimingField::FIRST_MEANINGFUL_PAINT);
+    waiter->Wait();
+  }
+
+  void WaitForTabsToLoad(Browser* browser) {
+    for (int i = 0; i < browser->tab_strip_model()->count(); ++i) {
+      content::WebContents* contents =
+          browser->tab_strip_model()->GetWebContentsAt(i);
+      contents->GetController().LoadIfNecessary();
+      content::WaitForLoadStop(contents);
+    }
+  }
+
+  GURL GetTestURL() const {
+    return embedded_test_server()->GetURL(
+        "/page_load_metrics/page_with_css.html");
+  }
+
+  GURL GetTestURL2() const {
+    return embedded_test_server()->GetURL(
+        "/page_load_metrics/main_frame_with_iframe.html");
+  }
+
+  void ExpectFirstPaintMetricsTotalCount(int expected_total_count) const {
+    // SessionRestorePageLoadMetricsObserver is disabled when browser-side
+    // navigation is enabled
+    histogram_tester_.ExpectTotalCount(
+        internal::kHistogramSessionRestoreForegroundTabFirstPaint,
+        expected_total_count);
+    histogram_tester_.ExpectTotalCount(
+        internal::kHistogramSessionRestoreForegroundTabFirstContentfulPaint,
+        expected_total_count);
+    histogram_tester_.ExpectTotalCount(
+        internal::kHistogramSessionRestoreForegroundTabFirstMeaningfulPaint,
+        expected_total_count);
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SessionRestorePageLoadMetricsBrowserTest);
+};
+
+IN_PROC_BROWSER_TEST_F(SessionRestorePageLoadMetricsBrowserTest,
+                       NoSessionRestore) {
+  ui_test_utils::NavigateToURL(browser(), GetTestURL());
+  // No metrics recorded because navigation is outside of session restore.
+  ExpectFirstPaintMetricsTotalCount(0);
+}
+
+IN_PROC_BROWSER_TEST_F(SessionRestorePageLoadMetricsBrowserTest,
+                       SingleTabSessionRestore) {
+  ui_test_utils::NavigateToURL(browser(), GetTestURL());
+  Browser* new_browser = QuitBrowserAndRestore(browser());
+  WaitForFirstMeaningfulPaintOfActiveTab(new_browser);
+  ExpectFirstPaintMetricsTotalCount(1);
+}
+
+IN_PROC_BROWSER_TEST_F(SessionRestorePageLoadMetricsBrowserTest,
+                       MultipleTabsSessionRestore) {
+  ui_test_utils::NavigateToURL(browser(), GetTestURL());
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GetTestURL(), WindowOpenDisposition::NEW_BACKGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  Browser* new_browser = QuitBrowserAndRestore(browser());
+
+  TabStripModel* tab_strip = new_browser->tab_strip_model();
+  ASSERT_TRUE(tab_strip);
+  ASSERT_EQ(2, tab_strip->count());
+
+  // Wait for first paints on the initial foreground tab and all tabs loaded.
+  WaitForFirstMeaningfulPaintOfActiveTab(new_browser);
+  WaitForTabsToLoad(new_browser);
+
+  // Only metrics of the initial foreground tab are recorded.
+  ExpectFirstPaintMetricsTotalCount(1);
+}
+
+IN_PROC_BROWSER_TEST_F(SessionRestorePageLoadMetricsBrowserTest,
+                       LoadingInForegroundTabInSessionRestore) {
+  ui_test_utils::NavigateToURL(browser(), GetTestURL());
+  Browser* new_browser = QuitBrowserAndRestore(browser());
+  // Ensure the session restore does not end when loading a new page.
+  scoped_refptr<TabLoader> tab_loader_retainer = TabLoader::shared_tab_loader_;
+
+  // Need to stop before loading a new page.
+  content::WebContents* active_web_contents =
+      new_browser->tab_strip_model()->GetActiveWebContents();
+  active_web_contents->Stop();
+  ExpectFirstPaintMetricsTotalCount(0);
+
+  auto waiter = base::MakeUnique<PageLoadMetricsWaiter>(active_web_contents);
+  waiter->AddPageExpectation(TimingField::FIRST_MEANINGFUL_PAINT);
+  ASSERT_TRUE(
+      g_browser_process->GetTabManager()->IsSessionRestoreLoadingTabs());
+  active_web_contents->GetController().LoadURL(
+      GetTestURL2(), content::Referrer(), ui::PAGE_TRANSITION_TYPED,
+      std::string());
+  waiter->Wait();
+
+  // Do not count the new page load in the initial foreground tab.
+  ExpectFirstPaintMetricsTotalCount(0);
+}
+
+IN_PROC_BROWSER_TEST_F(SessionRestorePageLoadMetricsBrowserTest,
+                       LoadingAfterSessionRestore) {
+  ui_test_utils::NavigateToURL(browser(), GetTestURL());
+  Browser* new_browser = QuitBrowserAndRestore(browser());
+
+  // Wait for session restore to finish (i.e., the end of the only tab).
+  WaitForFirstMeaningfulPaintOfActiveTab(new_browser);
+  ExpectFirstPaintMetricsTotalCount(1);
+
+  // Load a new page after session restore.
+  auto waiter = CreatePageLoadMetricsWaiter(
+      new_browser->tab_strip_model()->GetActiveWebContents());
+  waiter->AddPageExpectation(TimingField::FIRST_MEANINGFUL_PAINT);
+  ui_test_utils::NavigateToURL(new_browser, GetTestURL2());
+  waiter->Wait();
+
+  // No more metrics because the navigation is after session restore.
+  ExpectFirstPaintMetricsTotalCount(1);
+}
+
+IN_PROC_BROWSER_TEST_F(SessionRestorePageLoadMetricsBrowserTest,
+                       InitialForegroundTabChanged) {
+  ui_test_utils::NavigateToURL(browser(), GetTestURL());
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GetTestURL2(), WindowOpenDisposition::NEW_BACKGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  Browser* new_browser = QuitBrowserAndRestore(browser());
+
+  // Change the foreground tab before the first meaningful paint.
+  TabStripModel* tab_strip = new_browser->tab_strip_model();
+  ASSERT_TRUE(tab_strip);
+  ASSERT_EQ(2, tab_strip->count());
+  ASSERT_EQ(0, tab_strip->active_index());
+  tab_strip->ActivateTabAt(1, true);
+
+  // Wait for the first meaningful paint of the current foreground tab.
+  WaitForFirstMeaningfulPaintOfActiveTab(new_browser);
+  ExpectFirstPaintMetricsTotalCount(0);
+}
+
+IN_PROC_BROWSER_TEST_F(SessionRestorePageLoadMetricsBrowserTest,
+                       MultipleSessionRestores) {
+  ui_test_utils::NavigateToURL(browser(), GetTestURL());
+
+  Browser* current_browser = browser();
+  const int num_session_restores = 3;
+  for (int i = 1; i <= num_session_restores; ++i) {
+    current_browser = QuitBrowserAndRestore(current_browser);
+    WaitForFirstMeaningfulPaintOfActiveTab(current_browser);
+    ExpectFirstPaintMetricsTotalCount(i);
+  }
+}