From 1e3b08aae847915b48416f366fc755049e9ac03d Mon Sep 17 00:00:00 2001
From: Alan Jeffrey <ajeffrey@mozilla.com>
Date: Tue, 3 Sep 2019 11:03:45 -0500
Subject: [PATCH] Fallback to old extensions API if NUM_EXTENSIONS errors

---
 components/canvas/webgl_thread.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/components/canvas/webgl_thread.rs b/components/canvas/webgl_thread.rs
index 7844c762cfb..ceaaf908b9f 100644
--- a/components/canvas/webgl_thread.rs
+++ b/components/canvas/webgl_thread.rs
@@ -1727,6 +1727,11 @@ impl WebGLImpl {
         unsafe {
             gl.get_integer_v(gl::NUM_EXTENSIONS, &mut ext_count);
         }
+        // Fall back to the depricated extensions API if that fails
+        if gl.get_error() != gl::NO_ERROR {
+            chan.send(gl.get_string(gl::EXTENSIONS)).unwrap();
+            return;
+        }
         let ext_count = ext_count[0] as usize;
         let mut extensions = Vec::with_capacity(ext_count);
         for idx in 0..ext_count {