Apply WebGL validation to glVertexAttribIPointer.

TEST=deqp/functional/gles3/shaderstatequery.html
BUG=angleproject:1523
BUG=chromium:668223

Change-Id: I24230144f8529d84cdbde3d5a8ad9178481550a9
Reviewed-on: https://chromium-review.googlesource.com/458680
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/validationES3.cpp b/src/libANGLE/validationES3.cpp
index f5a0aa8..9c7d03d 100644
--- a/src/libANGLE/validationES3.cpp
+++ b/src/libANGLE/validationES3.cpp
@@ -2364,6 +2364,14 @@
         return false;
     }
 
+    if (context->getExtensions().webglCompatibility)
+    {
+        if (!ValidateWebGLVertexAttribPointer(context, type, false, stride, pointer, true))
+        {
+            return false;
+        }
+    }
+
     return true;
 }