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..b39ad24e38d3d235d74fb35eb9a5c4f8c8d229cb 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>
@@ -92,7 +95,7 @@ interface PPB_Graphics3D {
    * already shares with, and the newly created context. An arbitrary number of
    * <code>PPB_Graphics3D</code> can share data in this fashion.
    *
-   * @param[out] attrib_list specifies a list of attributes for the context.
+   * @param[in] attrib_list specifies a list of attributes for the context.
    * It is a list of attribute name-value pairs in which each attribute is
    * immediately followed by the corresponding desired value. The list is
    * terminated with <code>PP_GRAPHICS3DATTRIB_NONE</code>.