Replace GrGLInterface's function pointers with std::functions

src/gpu/gl/GrGLExtensions.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gl/GrGLExtensions.h"
 #include "gl/GrGLDefines.h"
 #include "gl/GrGLUtil.h"
@@ skipping 44 matching lines @@
             break;
         }
         // we found an extension
         size_t length = strcspn(in, " ");
         out->push_back().set(in, length);
         in += length;
     }
 }
 
 bool GrGLExtensions::init(GrGLStandard standard,
-                          GrGLGetStringProc getString,
-                          GrGLGetStringiProc getStringi,
-                          GrGLGetIntegervProc getIntegerv,
-                          GrEGLQueryStringProc queryString,
+                          GrGLFunction<GrGLGetStringProc> getString,
+                          GrGLFunction<GrGLGetStringiProc> getStringi,
+                          GrGLFunction<GrGLGetIntegervProc> getIntegerv,
+                          GrGLFunction<GrEGLQueryStringProc> queryString,
                           GrEGLDisplay eglDisplay) {
     fInitialized = false;
     fStrings->reset();
 
     if (!getString) {
         return false;
     }
 
     // glGetStringi and indexed extensions were added in version 3.0 of desktop GL and ES.
     const GrGLubyte* verString = getString(GR_GL_VERSION);
@@ skipping 69 matching lines @@
 
 void GrGLExtensions::print(const char* sep) const {
     if (nullptr == sep) {
         sep = " ";
     }
     int cnt = fStrings->count();
     for (int i = 0; i < cnt; ++i) {
         SkDebugf("%s%s", (*fStrings)[i].c_str(), (i < cnt - 1) ? sep : "");
     }
 }