Examples: GLFW+WebGPU: added support for WebGPU-native/Dawn (#7435, #7132)

examples/example_emscripten_wgpu/web/index.html

@@ -63,6 +63,10 @@
 
       // Initialize the graphics adapter
       {
+          if (!navigator.gpu) {
+            throw Error("WebGPU not supported.");
+          }
+
           const adapter = await navigator.gpu.requestAdapter();
           const device = await adapter.requestDevice();
           Module.preinitializedWebGPUDevice = device;