Add samples to Viewer.

tools/viewer/SKPSlide.h

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #ifndef SKPSlide_DEFINED
 #define SKPSlide_DEFINED
 
 #include "Slide.h"
 #include "SkPicture.h"
 
 class SKPSlide : public Slide {
 public:
     SKPSlide(const SkString& name, const SkString& path);
     ~SKPSlide() override;
 
     SkISize getDimensions() const override { return fCullRect.size(); }
 
     void draw(SkCanvas* canvas) override;
-    void load() override;
+    void load(SkScalar winWidth, SkScalar winHeight) override;
     void unload() override;
 
 private:
     SkString               fPath;
     sk_sp<const SkPicture> fPic;
     SkIRect                fCullRect;
 };
 
 #endif