jsdom, checker: add more methods for CanvasRenderingContext2D, fix interop check for JS methods (#12372)

vlib/jsdom/context.v

@@ -0,0 +1,34 @@
+// Wrapper around 2d context and WebGL APIs
+
+module jsdom
+
+pub struct ContextAttributes {
+pub:
+	alpha          bool
+	desynchronized bool
+}
+
+pub enum PowerPreference {
+	default_
+	high_performance
+	low_performance
+}
+
+pub struct WebGLAttributes {
+pub:
+	alpha                     bool
+	desynchronized            bool
+	antialias                 bool
+	depth                     bool
+	fail_if_major_perf_caveat bool
+	power_preference          PowerPreference
+	premultiplied_alpha       bool
+	preserve_drawing_buffer   bool
+	stencil                   bool
+}
+
+pub struct NoneContext {}
+
+pub type ContextResult = CanvasRenderingContext2D | NoneContext | WebGLRenderingContext
+
+pub struct JS.CanvasGradient {}