Observe input metrics from web content area.

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 5516e79a2d661b03360ed12af48582c656e1ed4b..c1c029803cb8a9756ce884f9819f5d34d05dea50 100644
--- a/chrome/browser/ui/browser_list.cc
+++ b/chrome/browser/ui/browser_list.cc
@@ -197,6 +197,12 @@ void BrowserList::SetLastActive(Browser* browser) {
 }
 
 // static
+void BrowserList::NotifyBrowserNoLongerActive(Browser* browser) {
+  FOR_EACH_OBSERVER(chrome::BrowserListObserver, observers_.Get(),
+                    OnBrowserNoLongerActive(browser));
+}
+
+// static
 bool BrowserList::IsOffTheRecordSessionActive() {
   for (auto* browser : *BrowserList::GetInstance()) {
     if (browser->profile()->IsOffTheRecord())