[Performance] improve atom.tooltips.add

[aminya]

You would be surprised if you know that most of the time spent for creating the buttons, is spent in adding the tooltips to them! We might want to write a faster version of the original https://github.com/suda/tool-bar/blob/937f75719a1002af5b207c073b6e45dd82617f44/lib/items/tool-bar-button-view.js#L121

https://github.com/atom/atom/blob/e4b9c1e0815c5c07514a0649e7ebb9b5226a2931/src/tooltip-manager.js#L113-L181

For 30 buttons, this becomes ~6ms.

Details

Which is almost the same as the whole time spent on the buttons:

Details

I am going to port the function to our package and see if I can write a faster version.

[aminya]

Further investigation shows that the time is spent here, to add keyBindingCommand, which is because we set keyBindingCommand even when the user gives it null
https://github.com/atom/atom/blob/e4b9c1e0815c5c07514a0649e7ebb9b5226a2931/src/tooltip-manager.js#L126-L139

  const { keyBindingCommand, keyBindingTarget } = options;

  if (keyBindingCommand != null) {
    const bindings = atom.tooltips.keymapManager.findKeyBindings({
      command: keyBindingCommand,
      target: keyBindingTarget
    });
    const keystroke = getKeystroke(bindings);
    if (options.title != null && keystroke != null) {
      options.title += ` ${getKeystroke(bindings)}`;
    } else if (keystroke != null) {
      options.title = getKeystroke(bindings);
    }
  }

We don't need to use keyBindingCommand, because we already add a callback through callback option, and tooltip callback is redundant.