Fixing drag and drop visibility issues of tabs on a visiting desktop

chrome/browser/ui/ash/launcher/browser_status_monitor.cc

Index: chrome/browser/ui/ash/launcher/browser_status_monitor.cc
diff --git a/chrome/browser/ui/ash/launcher/browser_status_monitor.cc b/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
index 2a925bc60d7ac97f4ea9f6a509632ac8640aae5d..2f1b5262c16e98e429c81f7fa425fc400cf6c622 100644
--- a/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
+++ b/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
@@ -97,8 +97,10 @@ void BrowserStatusMonitor::UpdateAppItemState(
     content::WebContents* contents,
     ChromeLauncherController::AppState app_state) {
   DCHECK(contents);
-  if (launcher_controller_->IsBrowserFromActiveUser(
-          chrome::FindBrowserWithWebContents(contents)))
+  // It is possible to come here from Browser::SwapTabContent where the contents
+  // cannot be associated with a browser.
+  Browser* browser = chrome::FindBrowserWithWebContents(contents);
+  if (browser && launcher_controller_->IsBrowserFromActiveUser(browser))
     launcher_controller_->UpdateAppState(contents, app_state);
 }