Improve GLSL integer support

src/gpu/gl/GrGLInterface.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "gl/GrGLInterface.h"
 #include "gl/GrGLExtensions.h"
@@ skipping 398 matching lines @@
     }
 
 
     // glGetStringi was added in version 3.0 of both desktop and ES.
     if (glVer >= GR_GL_VER(3, 0)) {
         if (nullptr == fFunctions.fGetStringi) {
             RETURN_FALSE_INTERFACE
         }
     }
 
+    // glVertexAttribIPointer was added in version 3.0 of both desktop and ES.
+    if (glVer >= GR_GL_VER(3, 0)) {
+        if (NULL == fFunctions.fVertexAttribIPointer) {
+            RETURN_FALSE_INTERFACE
+        }
+    }
+
     if (kGL_GrGLStandard == fStandard) {
         if (glVer >= GR_GL_VER(3, 0) || fExtensions.has("GL_ARB_vertex_array_object")) {
             if (nullptr == fFunctions.fBindVertexArray ||
                 nullptr == fFunctions.fDeleteVertexArrays ||
                 nullptr == fFunctions.fGenVertexArrays) {
                 RETURN_FALSE_INTERFACE
             }
         }
     } else {
         if (glVer >= GR_GL_VER(3,0) || fExtensions.has("GL_OES_vertex_array_object")) {
@@ skipping 319 matching lines @@
 
     if (fExtensions.has("EGL_KHR_image") || fExtensions.has("EGL_KHR_image_base")) {
         if (nullptr == fFunctions.fEGLCreateImage ||
             nullptr == fFunctions.fEGLDestroyImage) {
             RETURN_FALSE_INTERFACE
         }
     }
 
     return true;
 }