Revert of 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