Don't filter shortcut keys when a tab is opened in app ("windowed") mode.

chrome/browser/ui/browser.cc

Index: chrome/browser/ui/browser.cc
diff --git a/chrome/browser/ui/browser.cc b/chrome/browser/ui/browser.cc
index 0e242151653b62d9395cf48689895cefe7af45dc..aa95722d0fac922fd8129c708a7bcc13f8220f81 100644
--- a/chrome/browser/ui/browser.cc
+++ b/chrome/browser/ui/browser.cc
@@ -2975,6 +2975,10 @@ bool Browser::IsReservedCommandOrKey(int command_id,
   }
 #endif
 
+  // In Apps mode, no keys are reserved.
+  if (is_app())
+    return false;
+
   if (window_->IsFullscreen() && command_id == IDC_FULLSCREEN)
     return true;
   return command_id == IDC_CLOSE_TAB ||