Implement SkGLContext swapBuffers with fence syncs

include/gpu/gl/angle/SkANGLEGLContext.h

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkANGLEGLContext_DEFINED
 #define SkANGLEGLContext_DEFINED
 
 #if SK_ANGLE
 
 #include "gl/SkGLContext.h"
 
 class SkANGLEGLContext : public SkGLContext {
 public:
     ~SkANGLEGLContext() override;
-    void makeCurrent() const override;
-    void swapBuffers() const override;
 
     static SkANGLEGLContext* Create(GrGLStandard forcedGpuAPI) {
         if (kGL_GrGLStandard == forcedGpuAPI) {
             return NULL;
         }
         SkANGLEGLContext* ctx = SkNEW(SkANGLEGLContext);
         if (!ctx->isValid()) {
             SkDELETE(ctx);
             return NULL;
         }
         return ctx;
     }
 
     // The param is an EGLNativeDisplayType and the return is an EGLDispay.
     static void* GetD3DEGLDisplay(void* nativeDisplay);
 
 private:
     SkANGLEGLContext();
     void destroyGLContext();
 
+    void onPlatformMakeCurrent() const override;
+    void onPlatformSwapBuffers() const override;
+    GrGLFuncPtr onPlatformGetProcAddress(const char* name) const override;
+
     void* fContext;
     void* fDisplay;
     void* fSurface;
 };
 
 #endif
 
 #endif