webgl: Remove active_uniform related validation.

It's broken for uniform arrays, since uniform.id() stops being the index
then.

We need to add a more complex integration with angle for this to ever
be correct.

Unfortunately the ANGLE part that we should touch is C++, and it has
destructors, so we need to hook destructors there, and I can't do it
right now.

components/script/dom/webglshader.rs

@@ -116,6 +116,11 @@ impl WebGLShader {
             }
 
             *self.info_log.borrow_mut() = Some(validator.info_log());
+            // TODO(emilio): More data (like uniform data) should be collected
+            // here to properly validate uniforms.
+            //
+            // This requires a more complex interface with ANGLE, using C++
+            // bindings and being extremely cautious about destructing things.
         }
     }