(Bloomberg) -- Emma Walmsley may have bolstered her position at the top of GlaxoSmithKline Plc, at least for now, following a lukewarm reaction to long-awaited plans to restructure the pharmaceutical giant after years of underperformance.With a potential activist investor challenge looming from Elliott Management Corp., Walmsley laid out why she thinks she is the right “change agent” to run the pharmaceutical business that will be left once Glaxo finally carves out its consumer arm via a de-merger.Glaxo shares ended the day up only 1% in London, with investors requiring faith that the company will be able to follow through on …