WIP refactor rerender render-v2

frontend/render_v2/cpp/js/preamble.js

@@ -0,0 +1,20 @@
+// Adds compile-time JS functions to augment Renderer interface.
+(function (Renderer) {
+  console.log("preamble", Renderer);
+  Renderer.setCanvas = function setCanvas(canvas, attrs) {
+    console.log("GL", GL);
+    debugger
+    const context = GL.createContext(canvas, attrs);
+    if (!context) {
+      throw new Error('Could not create a new WebGL context')
+    }
+    GL.makeContextCurrent(context);
+
+    // Emscripten does not enable this by default and Skia needs this
+    // to handle certain GPU corner cases.
+    GL.currentContext.GLctx.getExtension('WEBGL_debug_renderer_info');
+
+    console.log("setCanvas", canvas, attrs);
+    const gr  = this._MakeGrContext();
+    console.log("gr", gr);
+  };