[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 af8a1774b67285945b79dcfa1788dbfec3a56c75..0181c8fed43a6ac4be27642ab6ba1ef0a7bcfaf0 100644
--- a/chrome/browser/resource_coordinator/tab_manager.cc
+++ b/chrome/browser/resource_coordinator/tab_manager.cc
@@ -111,6 +111,8 @@ TabManager::TabManager()
 #endif
       browser_tab_strip_tracker_(this, nullptr, nullptr),
       test_tick_clock_(nullptr),
+      is_during_session_restore_(false),
+      initial_active_tab_changed_(false),
       weak_ptr_factory_(this) {
 #if defined(OS_CHROMEOS)
   delegate_.reset(new TabManagerDelegate(weak_ptr_factory_.GetWeakPtr()));
@@ -792,6 +794,10 @@ void TabManager::ActiveTabChanged(content::WebContents* old_contents,
     GetWebContentsData(old_contents)
         ->set_time_to_purge(GetTimeToPurge(min_time_to_purge_));
   }
+
+  if (old_contents && !initial_active_tab_changed_) {
+    initial_active_tab_changed_ = true;
+  }
 }
 
 void TabManager::TabInsertedAt(TabStripModel* tab_strip_model,