Use glGetStringi to get extensions when available.
Review URL: https://codereview.chromium.org/12328111

git-svn-id: http://skia.googlecode.com/svn/trunk@7872 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/gl/GrGLCreateNullInterface.cpp b/src/gpu/gl/GrGLCreateNullInterface.cpp
index d221218..da6491a 100644
--- a/src/gpu/gl/GrGLCreateNullInterface.cpp
+++ b/src/gpu/gl/GrGLCreateNullInterface.cpp
@@ -215,6 +215,7 @@
         interface->fGetShaderInfoLog = noOpGLGetInfoLog;
         interface->fGetShaderiv = noOpGLGetShaderOrProgramiv;
         interface->fGetString = noOpGLGetString;
+        interface->fGetStringi = noOpGLGetStringi;
         interface->fGetTexLevelParameteriv = noOpGLGetTexLevelParameteriv;
         interface->fGetUniformLocation = noOpGLGetUniformLocation;
         interface->fLineWidth = noOpGLLineWidth;