Implement ES3.1 glDraw*Indirect entry points for OpenGL

BUG=angleproject:1595
TEST=dEQP-GLES31.functional.draw_indirect.*

Change-Id: I82f5d0864e70d6e7abdccf5f10330ddfa099ec62
Reviewed-on: https://chromium-review.googlesource.com/417250
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/renderer/null/ContextNULL.cpp b/src/libANGLE/renderer/null/ContextNULL.cpp
index 77fa0ab..2bddec0 100644
--- a/src/libANGLE/renderer/null/ContextNULL.cpp
+++ b/src/libANGLE/renderer/null/ContextNULL.cpp
@@ -101,6 +101,16 @@
     return gl::NoError();
 }
 
+gl::Error ContextNULL::drawArraysIndirect(GLenum mode, const GLvoid *indirect)
+{
+    return gl::NoError();
+}
+
+gl::Error ContextNULL::drawElementsIndirect(GLenum mode, GLenum type, const GLvoid *indirect)
+{
+    return gl::NoError();
+}
+
 void ContextNULL::stencilFillPath(const gl::Path *path, GLenum fillMode, GLuint mask)
 {
 }