Simplify VertexAttribOffset

components/canvas/webgl_thread.rs

@@ -1104,12 +1104,8 @@ impl WebGLImpl {
     fn vertex_attrib_offset(gl: &gl::Gl,
                             index: u32,
                             pname: u32,
-                            chan: WebGLSender<WebGLResult<isize>>) {
-        let result = match pname {
-                gl::VERTEX_ATTRIB_ARRAY_POINTER => Ok(gl.get_vertex_attrib_pointer_v(index, pname)),
-                _ => Err(WebGLError::InvalidEnum),
-        };
-
+                            chan: WebGLSender<isize>) {
+        let result = gl.get_vertex_attrib_pointer_v(index, pname);
         chan.send(result).unwrap();
     }
 

components/canvas_traits/webgl.rs

@@ -216,7 +216,7 @@ pub enum WebGLCommand {
     GetAttribLocation(WebGLProgramId, String, WebGLSender<Option<i32>>),
     GetUniformLocation(WebGLProgramId, String, WebGLSender<Option<i32>>),
     GetVertexAttrib(u32, u32, WebGLSender<WebGLResult<WebGLParameter>>),
-    GetVertexAttribOffset(u32, u32, WebGLSender<WebGLResult<isize>>),
+    GetVertexAttribOffset(u32, u32, WebGLSender<isize>),
     GetShaderInfoLog(WebGLShaderId, WebGLSender<String>),
     GetProgramInfoLog(WebGLProgramId, WebGLSender<String>),
     PolygonOffset(f32, f32),

components/script/dom/webglrenderingcontext.rs

@@ -2421,10 +2421,14 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn GetVertexAttribOffset(&self, index: u32, pname: u32) -> i64 {
+        if pname != constants::VERTEX_ATTRIB_ARRAY_POINTER {
+            self.webgl_error(InvalidEnum);
+            return 0;
+        }
         let (sender, receiver) = webgl_channel().unwrap();
         self.send_command(WebGLCommand::GetVertexAttribOffset(index, pname, sender));
 
-        handle_potential_webgl_error!(self, receiver.recv().unwrap(), 0) as i64
+        receiver.recv().unwrap()
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.3