Revert of Add OpenGL context to Viewer.

tools/viewer/sk_app/WindowContext.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 WindowContext_DEFINED
 #define WindowContext_DEFINED
 
 #include "DisplayParams.h"
 #include "GrTypes.h"
-#include "SkRefCnt.h"
-#include "SkSurfaceProps.h"
 
-class GrContext;
 class SkSurface;
-class GrRenderTarget;
 
 namespace sk_app {
 
+// TODO: fill this out with an interface
 class WindowContext {
 public:
-    WindowContext() : fContext(nullptr)
-                    , fSurfaceProps(SkSurfaceProps::kLegacyFontHost_InitType) {}
-
     virtual ~WindowContext() {}
 
-    virtual sk_sp<SkSurface> getBackbufferSurface() = 0;
+    virtual SkSurface* getBackbufferSurface() = 0;
 
     virtual void swapBuffers() = 0;
 
+    virtual bool makeCurrent() = 0;
+
     virtual bool isValid() = 0;
 
     virtual void resize(uint32_t w, uint32_t h) = 0;
 
-    const DisplayParams& getDisplayParams() { return fDisplayParams; }
+    virtual const DisplayParams& getDisplayParams() = 0;
     virtual void setDisplayParams(const DisplayParams& params) = 0;
 
-    SkSurfaceProps getSurfaceProps() const { return fSurfaceProps; }
-    void setSurfaceProps(const SkSurfaceProps& props) {
-        fSurfaceProps = props;
-    }
-
     virtual GrBackendContext getBackendContext() = 0;
-
-    sk_sp<SkSurface> createRenderSurface(sk_sp<GrRenderTarget>, int colorBits);
-    void presentRenderSurface(sk_sp<SkSurface> renderSurface, sk_sp<GrRenderTarget> rt,
-                              int colorBits);
-
-protected:
-    virtual bool isGpuContext() { return true;  }
-
-    GrContext*        fContext;
-
-    int               fWidth;
-    int               fHeight;
-    DisplayParams     fDisplayParams;
-    GrPixelConfig     fPixelConfig;
-    SkSurfaceProps    fSurfaceProps;
 };
 
 }   // namespace sk_app
 
 #endif