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

chrome/browser/resource_coordinator/tab_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/resource_coordinator/tab_manager.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <set>
@@ skipping 126 matching lines @@
 TabManager::TabManager()
     : discard_count_(0),
       recent_tab_discard_(false),
       discard_once_(false),
 #if !defined(OS_CHROMEOS)
       minimum_protection_time_(base::TimeDelta::FromMinutes(10)),
 #endif
       browser_tab_strip_tracker_(this, nullptr, this),
       test_tick_clock_(nullptr),
       is_session_restore_loading_tabs_(false),
+      initial_session_restore_foreground_tab_changed_(false),
       weak_ptr_factory_(this) {
 #if defined(OS_CHROMEOS)
   delegate_.reset(new TabManagerDelegate(weak_ptr_factory_.GetWeakPtr()));
 #endif
   browser_tab_strip_tracker_.Init();
   session_restore_observer_.reset(new TabManagerSessionRestoreObserver(this));
 }
 
 TabManager::~TabManager() {
   Stop();
@@ skipping 318 matching lines @@
   // Being more recently active is more important.
   return first.last_active > second.last_active;
 }
 
 // static
 int64_t TabManager::IdFromWebContents(WebContents* web_contents) {
   return reinterpret_cast<int64_t>(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() {
   DCHECK(is_session_restore_loading_tabs_);
   is_session_restore_loading_tabs_ = false;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // TabManager, private:
 
@@ skipping 322 matching lines @@
   }
 
   // An active tab is not purged.
   GetWebContentsData(new_contents)->set_is_purged(false);
 
   // Reload |web_contents| if it is in an active browser and discarded.
   if (IsActiveWebContentsInActiveBrowser(new_contents)) {
     ReloadWebContentsIfDiscarded(new_contents,
                                  GetWebContentsData(new_contents));
   }
+
+  if (old_contents && !initial_session_restore_foreground_tab_changed_) {
+    initial_session_restore_foreground_tab_changed_ = true;
+  }
 }
 
 void TabManager::TabInsertedAt(TabStripModel* tab_strip_model,
                                content::WebContents* contents,
                                int index,
                                bool foreground) {
   // Only interested in background tabs, as foreground tabs get taken care of by
   // ActiveTabChanged.
   if (foreground)
     return;
@@ skipping 116 matching lines @@
 
 void TabManager::RecordSwitchToTab(content::WebContents* contents) const {
   if (is_session_restore_loading_tabs_) {
     UMA_HISTOGRAM_ENUMERATION("TabManager.SessionRestore.SwitchToTab",
                               GetWebContentsData(contents)->tab_loading_state(),
                               TAB_LOADING_STATE_MAX);
   }
 }
 
 }  // namespace resource_coordinator