Adds support for showing accelerators in bookmark menus.

views/accelerator.h

Index: views/accelerator.h
diff --git a/views/accelerator.h b/views/accelerator.h
index 82be336b60aef13deb714f85c88f1e22db5d1d32..a54a431380ce7f85efef7ee88a9c282cb682a90b 100644
--- a/views/accelerator.h
+++ b/views/accelerator.h
@@ -20,6 +20,8 @@ namespace views {
 
 class Accelerator : public menus::Accelerator {
  public:
+  Accelerator() : menus::Accelerator() {}
+
   Accelerator(base::KeyboardCode keycode,
               bool shift_pressed, bool ctrl_pressed, bool alt_pressed) {
     key_code_ = keycode;