src/vs/platform/keybinding/common/keybindingResolver.ts/KeybindingResolver/_removeFromLookupMap
class KeybindingResolver:	private _removeFromLookupMap(item: ResolvedKeybindingItem): void {
		if (!item.command) {
			return;
		}
		let arr = this._lookupMap.get(item.command);
		if (typeof arr === 'undefined') {
			return;
		}
		for (let i = 0, len = arr.length; i < len; i++) {
			if (arr[i] === item) {
				arr.splice(i, 1);
				return;
			}
		}
	}