Fail to create GrContext when we get a NULL for a GL/GLSL version string

src/gpu/gl/GrGLInterface.cpp

Index: src/gpu/gl/GrGLInterface.cpp
diff --git a/src/gpu/gl/GrGLInterface.cpp b/src/gpu/gl/GrGLInterface.cpp
index b5da4d3a95982a09c6348d999ca5d419a209b299..7efa067ddbb180c69a23e1b04e826baade418b6b 100644
--- a/src/gpu/gl/GrGLInterface.cpp
+++ b/src/gpu/gl/GrGLInterface.cpp
@@ -227,6 +227,9 @@ bool GrGLInterface::validate() const {
     }
 
     GrGLVersion glVer = GrGLGetVersion(this);
+    if (GR_GL_INVALID_VER == glVer) {
+        RETURN_FALSE_INTERFACE
+    }
 
     // Now check that baseline ES/Desktop fns not covered above are present
     // and that we have fn pointers for any advertised fExtensions that we will