Fix crash when opening web app menu while no tabs are loaded

This CL adds a simple nullptr check to the web app menu for when the
browser window has no tabs selected.

Screenshot of no minor text:
https://bugs.chromium.org/p/chromium/issues/attachment?aid=457537&signed_aid=Kjcn9nX_y395O5ZsqKkjjw==&inline=1

Bug: 1103331
Change-Id: I79c2f02edebde35772f6cd7c34f8e8c610f56040
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2309769
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Auto-Submit: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790585}

chrome/browser/ui/web_applications/web_app_browsertest.cc

@@ -527,6 +527,17 @@ IN_PROC_BROWSER_TEST_P(WebAppBrowserTest, PopOutDisabledInIncognito) {
   EXPECT_FALSE(model->IsEnabledAt(index));
 }
 
+// Tests that web app menus don't crash when no tabs are selected.
+IN_PROC_BROWSER_TEST_P(WebAppBrowserTest, NoTabSelectedMenuCrash) {
+  const GURL app_url = GetSecureAppURL();
+  const AppId app_id = InstallPWA(app_url);
+  Browser* const app_browser = LaunchWebAppBrowserAndWait(app_id);
+
+  app_browser->tab_strip_model()->CloseAllTabs();
+  auto app_menu_model = std::make_unique<WebAppMenuModel>(nullptr, app_browser);
+  app_menu_model->Init();
+}
+
 // Tests that PWA menus have an uninstall option.
 IN_PROC_BROWSER_TEST_P(WebAppBrowserTest, UninstallMenuOption) {
   const GURL app_url = GetSecureAppURL();

chrome/browser/ui/web_applications/web_app_menu_model.cc

@@ -50,11 +50,12 @@ void WebAppMenuModel::Build() {
   AddItemWithStringId(IDC_WEB_APP_MENU_APP_INFO,
                       IDS_APP_CONTEXT_MENU_SHOW_INFO);
   int app_info_index = GetItemCount() - 1;
-  SetMinorText(app_info_index, web_app::AppBrowserController::FormatUrlOrigin(
-                                   browser()
-                                       ->tab_strip_model()
-                                       ->GetActiveWebContents()
-                                       ->GetVisibleURL()));
+  content::WebContents* web_contents =
+      browser()->tab_strip_model()->GetActiveWebContents();
+  if (web_contents) {
+    SetMinorText(app_info_index, web_app::AppBrowserController::FormatUrlOrigin(
+                                     web_contents->GetVisibleURL()));
+  }
   SetMinorIcon(app_info_index,
                ui::ImageModel::FromVectorIcon(
                    browser()->location_bar_model()->GetVectorIcon()));