Enable keyboard shortcuts and some menu commands for browserless Panels.

chrome/browser/ui/panels/panel_cocoa.mm

Index: chrome/browser/ui/panels/panel_cocoa.mm
diff --git a/chrome/browser/ui/panels/panel_cocoa.mm b/chrome/browser/ui/panels/panel_cocoa.mm
index 6d64a4525114f17c103a54886a2e91f1e13be3c2..eb38a92fddef069d2515d290db2145553342408d 100644
--- a/chrome/browser/ui/panels/panel_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_cocoa.mm
@@ -199,13 +199,19 @@ bool PanelCocoa::IsDrawingAttention() const {
 
 bool PanelCocoa::PreHandlePanelKeyboardEvent(
     const NativeWebKeyboardEvent& event, bool* is_keyboard_shortcut) {
-  // TODO(jennb): any shortcut handling needed for Panel?
+  // No need to prehandle as no keys are reserved.
   return false;
 }
 
 void PanelCocoa::HandlePanelKeyboardEvent(
     const NativeWebKeyboardEvent& event) {
-  // TODO(jennb): any shortcut handling needed for Panel?
+  if (event.skip_in_browser || event.type == NativeWebKeyboardEvent::Char)
+    return;
+
+  ChromeEventProcessingWindow* event_window =
+      static_cast<ChromeEventProcessingWindow*>([controller_ window]);
+  DCHECK([event_window isKindOfClass:[ChromeEventProcessingWindow class]]);
+  [event_window redispatchKeyEvent:event.os_event];
 }
 
 void PanelCocoa::FullScreenModeChanged(