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

chrome/browser/resource_coordinator/tab_manager.cc

Index: chrome/browser/resource_coordinator/tab_manager.cc
diff --git a/chrome/browser/resource_coordinator/tab_manager.cc b/chrome/browser/resource_coordinator/tab_manager.cc
index 7332949cbdacd598ba3f6665fb179a7af6a3ae0e..846d73c0a561ed81bcab7e826da259044e033545 100644
--- a/chrome/browser/resource_coordinator/tab_manager.cc
+++ b/chrome/browser/resource_coordinator/tab_manager.cc
@@ -155,6 +155,7 @@ TabManager::TabManager()
       browser_tab_strip_tracker_(this, nullptr, this),
       test_tick_clock_(nullptr),
       is_session_restore_loading_tabs_(false),
+      initial_session_restore_foreground_tab_changed_(false),
       force_load_timer_(base::MakeUnique<base::OneShotTimer>()),
       weak_ptr_factory_(this) {
 #if defined(OS_CHROMEOS)
@@ -515,6 +516,9 @@ int64_t TabManager::IdFromWebContents(WebContents* web_contents) {
 void TabManager::OnSessionRestoreStartedLoadingTabs() {
   DCHECK(!is_session_restore_loading_tabs_);
   is_session_restore_loading_tabs_ = true;
+
+  // Needs to reset this flag for each session restore.
+  initial_session_restore_foreground_tab_changed_ = false;
 }
 
 void TabManager::OnSessionRestoreFinishedLoadingTabs() {
@@ -887,6 +891,15 @@ void TabManager::ActiveTabChanged(content::WebContents* old_contents,
   }
 
   ResumeTabNavigationIfNeeded(new_contents);
+
+  if (old_contents && !initial_session_restore_foreground_tab_changed_) {
+    RestoreOrigin* restore_origin =
+        RestoreOrigin::FromWebContents(old_contents);
+    if (restore_origin &&
+        restore_origin->type() == RestoreOrigin::Type::SESSION_RESTORE) {
+      initial_session_restore_foreground_tab_changed_ = true;
+    }
+  }
 }
 
 void TabManager::TabInsertedAt(TabStripModel* tab_strip_model,