Bug fix: Use the last hidden time for purge + suspend

chrome/browser/memory/tab_manager.cc

Index: chrome/browser/memory/tab_manager.cc
diff --git a/chrome/browser/memory/tab_manager.cc b/chrome/browser/memory/tab_manager.cc
index e761e81a7c43a1d31ef1ebd15c33c984e6faa98b..0f71308419f82d42bac643dc02b210dec450fa74 100644
--- a/chrome/browser/memory/tab_manager.cc
+++ b/chrome/browser/memory/tab_manager.cc
@@ -639,6 +639,7 @@ void TabManager::AddTabStats(const TabStripModel* model,
           contents->GetPageImportanceSignals().had_form_interaction;
       stats.discard_count = GetWebContentsData(contents)->DiscardCount();
       stats.last_active = contents->GetLastActiveTime();
+      stats.last_hidden = contents->GetLastHiddenTime();
       stats.render_process_host = contents->GetRenderProcessHost();
       stats.renderer_handle = contents->GetRenderProcessHost()->GetHandle();
       stats.child_process_host_id = contents->GetRenderProcessHost()->GetID();
@@ -710,7 +711,7 @@ void TabManager::PurgeAndSuspendBackgroundedTabs() {
     // timers for simplicity, so PurgeAndSuspend is called even after the
     // renderer is purged and suspended once. This should be replaced with
     // timers if we want necessary and sufficient signals.
-    if (tab.last_active > purge_and_suspend_time_threshold)
+    if (tab.last_hidden > purge_and_suspend_time_threshold)
       continue;
     if (!CanSuspendBackgroundedRenderer(tab.child_process_host_id))
       continue;