Add fence support for TransferBuffers

src/gpu/gl/GrGLTestInterface.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 GrGLTestInterface_DEFINED
 #define GrGLTestInterface_DEFINED
 
@@ skipping 299 matching lines @@
     virtual GrGLvoid disableVertexArray(GrGLuint vaobj, GrGLenum array) {}
     virtual GrGLvoid enableVertexArrayAttrib(GrGLuint vaobj, GrGLuint index) {}
     virtual GrGLvoid disableVertexArrayAttrib(GrGLuint vaobj, GrGLuint index) {}
     virtual GrGLvoid getVertexArrayIntegerv(GrGLuint vaobj, GrGLenum pname, GrGLint *param) {}
     virtual GrGLvoid getVertexArrayPointerv(GrGLuint vaobj, GrGLenum pname, GrGLvoid **param) {}
     virtual GrGLvoid getVertexArrayIntegeri_v(GrGLuint vaobj, GrGLuint index, GrGLenum pname, GrGLint *param) {}
     virtual GrGLvoid getVertexArrayPointeri_v(GrGLuint vaobj, GrGLuint index, GrGLenum pname, GrGLvoid **param) {}
     virtual GrGLvoid* mapNamedBufferRange(GrGLuint buffer, GrGLintptr offset, GrGLsizeiptr length, GrGLbitfield access) { return nullptr; }
     virtual GrGLvoid flushMappedNamedBufferRange(GrGLuint buffer, GrGLintptr offset, GrGLsizeiptr length) {}
     virtual GrGLvoid textureBuffer(GrGLuint texture, GrGLenum target, GrGLenum internalformat, GrGLuint buffer) {}
+    virtual GrGLsync fenceSync(GrGLenum condition, GrGLbitfield flags) { return nullptr;  }
+    virtual GrGLenum clientWaitSync(GrGLsync sync, GrGLbitfield flags, GrGLuint64 timeout) { return GR_GL_WAIT_FAILED;  }
+    virtual GrGLvoid deleteSync(GrGLsync sync) {}
     virtual GrGLvoid debugMessageControl(GrGLenum source, GrGLenum type, GrGLenum severity, GrGLsizei count, const GrGLuint* ids, GrGLboolean enabled) {}
     virtual GrGLvoid debugMessageInsert(GrGLenum source, GrGLenum type, GrGLuint id, GrGLenum severity, GrGLsizei length,  const GrGLchar* buf) {}
     virtual GrGLvoid debugMessageCallback(GRGLDEBUGPROC callback, const GrGLvoid* userParam) {}
     virtual GrGLuint getDebugMessageLog(GrGLuint count, GrGLsizei bufSize, GrGLenum* sources, GrGLenum* types, GrGLuint* ids, GrGLenum* severities, GrGLsizei* lengths,  GrGLchar* messageLog) { return 0; }
     virtual GrGLvoid pushDebugGroup(GrGLenum source, GrGLuint id, GrGLsizei length,  const GrGLchar * message) {}
     virtual GrGLvoid popDebugGroup() {}
     virtual GrGLvoid objectLabel(GrGLenum identifier, GrGLuint name, GrGLsizei length, const GrGLchar *label) {}
 
 protected:
     // This must be called by leaf class
     void init(GrGLStandard standard) {
         fStandard = standard;
         fExtensions.init(standard, fFunctions.fGetString, fFunctions.fGetStringi,
                          fFunctions.fGetIntegerv, nullptr, GR_EGL_NO_DISPLAY);
     }
     GrGLTestInterface();
 };
 
 #endif