Add desktop engagement metrics.

chrome/browser/ui/browser_list.cc

Index: chrome/browser/ui/browser_list.cc
diff --git a/chrome/browser/ui/browser_list.cc b/chrome/browser/ui/browser_list.cc
index 04c7021064e36476a5368d525279b7485c5bf970..43a881a9ed958fad6823cd0ec0c5c4c5e903cefc 100644
--- a/chrome/browser/ui/browser_list.cc
+++ b/chrome/browser/ui/browser_list.cc
@@ -228,6 +228,12 @@ void BrowserList::SetLastActive(Browser* browser) {
 }
 
 // static
+void BrowserList::NotifyBrowserNoLongerActive(Browser* browser) {
+  FOR_EACH_OBSERVER(chrome::BrowserListObserver, observers_.Get(),
+                    OnBrowserNoLongerActive(browser));
+}
+
+// static
 bool BrowserList::IsIncognitoSessionActive() {
   for (auto* browser : *BrowserList::GetInstance()) {
     if (browser->profile()->IsOffTheRecord())