1. @DomName('WebGL2RenderingContext.getUniformBlockIndex')
  2. @DocsEditable()
  3. @Experimental()
int getUniformBlockIndex(Program program, String uniformBlockName)

Source 

@DomName('WebGL2RenderingContext.getUniformBlockIndex')
@DocsEditable()
@Experimental() // untriaged
int getUniformBlockIndex(Program program, String uniformBlockName) =>
    _blink.BlinkWebGL2RenderingContext.instance
        .getUniformBlockIndex_Callback_2_(this, program, uniformBlockName);