src/vs/workbench/browser/composite.ts/CompositeRegistry/registerComposite
class CompositeRegistry:	protected registerComposite(descriptor: CompositeDescriptor<T>): void {
		if (this.compositeById(descriptor.id)) {
			return;
		}

		this.composites.push(descriptor);
		this._onDidRegister.fire(descriptor);
	}