Fix ppb_graphics_3d example code

ppapi/api/ppb_graphics_3d.idl

Index: ppapi/api/ppb_graphics_3d.idl
diff --git a/ppapi/api/ppb_graphics_3d.idl b/ppapi/api/ppb_graphics_3d.idl
index 28a0c40d7a6c803bf545db039ca115a38d656b03..405e1d7354a0e35545962b55dc66646ea33f28e8 100644
--- a/ppapi/api/ppb_graphics_3d.idl
+++ b/ppapi/api/ppb_graphics_3d.idl
@@ -29,14 +29,17 @@ label Chrome {
  * int32_t attribs[] = {PP_GRAPHICS3DATTRIB_WIDTH, 800,
  *                      PP_GRAPHICS3DATTRIB_HEIGHT, 800,
  *                      PP_GRAPHICS3DATTRIB_NONE};
- * context = g3d->Create(instance, attribs, &context);
+ * context = g3d->Create(instance, 0, attribs);
  * inst->BindGraphics(instance, context);
  * @endcode
  *
  * <strong>Present one frame:</strong>
  * @code
- * gles2->Clear(context, GL_COLOR_BUFFER);
- * g3d->SwapBuffers(context);
+ * PP_CompletionCallback callback = {
+ *   DidFinishSwappingBuffers, 0, PP_COMPLETIONCALLBACK_FLAG_NONE,
+ * };
+ * gles2->Clear(context, GL_COLOR_BUFFER_BIT);
+ * g3d->SwapBuffers(context, callback);
  * @endcode
  *
  * <strong>Shutdown:</strong>