More cleanup in the Vulkan viewer

tools/vulkan/viewer/GMSlide.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 /*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "GMSlide.h"
 #include "SkCanvas.h"
 
 GMSlide::GMSlide(skiagm::GM* gm) : fGM(gm) {
     fName.printf("GM_%s", gm->getName());
 }
 
 GMSlide::~GMSlide() { delete fGM; }
 
 void GMSlide::draw(SkCanvas* canvas) {
     // Do we care about timing the draw of the background (once)?
     // Does the GM ever rely on drawBackground to lazily compute something?
     fGM->drawBackground(canvas);
     fGM->drawContent(canvas);
 }
+
+bool GMSlide::animate(const SkAnimTimer& timer) {
+    return fGM->animate(timer);
+}