Add samples to Viewer.

tools/viewer/SampleSlide.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 SampleSlide_DEFINED
+#define SampleSlide_DEFINED
+
+#include "Slide.h"
+#include "SampleCode.h"
+
+class SampleSlide : public Slide {
+public:
+    SampleSlide(const SkViewFactory* factory);
+    ~SampleSlide() override;
+
+    void draw(SkCanvas* canvas) override;
+    void load(SkScalar winWidth, SkScalar winHeight) override;
+    void unload() override;
+    bool animate(const SkAnimTimer& timer) override {
+        if (SampleView::IsSampleView(fView)) {
+            return ((SampleView*)fView)->animate(timer);
+        }
+        return false;
+    }
+
+private:
+    const SkViewFactory*   fViewFactory;
+    SkView*                fView;
+};
+
+#endif