1. @DomName('WebGLRenderingContext.getExtension')
  2. @DocsEditable()
Object getExtension(String name)

Source 

@DomName('WebGLRenderingContext.getExtension')
@DocsEditable()
Object getExtension(String name) =>
    (_blink.BlinkWebGLRenderingContext.instance
        .getExtension_Callback_1_(this, name));