Implement robust the GetBufferPointerv entry point.

BUG=angleproject:1354

Change-Id: Id7dd8438224adb1e2729bcdc18a306e5dfc83a3b
Reviewed-on: https://chromium-review.googlesource.com/401399
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/queryutils.h b/src/libANGLE/queryutils.h
index 6cf3e6a..28a84b3 100644
--- a/src/libANGLE/queryutils.h
+++ b/src/libANGLE/queryutils.h
@@ -32,6 +32,7 @@
                                            GLint *params);
 void QueryBufferParameteriv(const Buffer *buffer, GLenum pname, GLint *params);
 void QueryBufferParameteri64v(const Buffer *buffer, GLenum pname, GLint64 *params);
+void QueryBufferPointerv(const Buffer *buffer, GLenum pname, void **params);
 void QueryProgramiv(const Program *program, GLenum pname, GLint *params);
 void QueryRenderbufferiv(const Renderbuffer *renderbuffer, GLenum pname, GLint *params);
 void QueryShaderiv(const Shader *shader, GLenum pname, GLint *params);