Implement SkGLContext swapBuffers with fence syncs

src/gpu/gl/mesa/SkMesaGLContext.h

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkMesaGLContext_DEFINED
 #define SkMesaGLContext_DEFINED
 
 #include "gl/SkGLContext.h"
 
 #if SK_MESA
 
 class SkMesaGLContext : public SkGLContext {
 private:
     typedef intptr_t Context;
 
 public:
     ~SkMesaGLContext() override;
-    void makeCurrent() const override;
-    void swapBuffers() const override;
 
     static SkMesaGLContext* Create(GrGLStandard forcedGpuAPI) {
         if (kGLES_GrGLStandard == forcedGpuAPI) {
             return NULL;
         }
         SkMesaGLContext* ctx = SkNEW(SkMesaGLContext);
         if (!ctx->isValid()) {
             SkDELETE(ctx);
             return NULL;
         }
         return ctx;
     }
 
 private:
     SkMesaGLContext();
     void destroyGLContext();
 
+    void onPlatformMakeCurrent() const override;
+    void onPlatformSwapBuffers() const override;
+    GrGLFuncPtr onPlatformGetProcAddress(const char*) const override;
+
     Context fContext;
     GrGLubyte *fImage;
 };
 
 #endif
 
 #endif