Move session request feature before session creation

Author: Manishearth

index.bs

@@ -368,15 +368,15 @@ When this method is invoked, the user agent MUST run the following steps:
             1. [=Reject=] |promise| with a "{{NotSupportedError}}" {{DOMException}}.
             1. If |immersive| is <code>true</code>, set [=pending immersive session=] to <code>false</code>.
             1. Abort these steps.
-        1. Let |session| be a new {{XRSession}} object.
-        1. [=Initialize the session=] with |session|, |mode|, and |device|.
         1. Let |descriptor| be an {{XRPermissionDescriptor}} initialized with |mode|, |requiredFeatures|, and |optionalFeatures|
         1. Let |status| be an {{XRPermissionStatus}}, initially <code>null</code>
         1. [=Request the xr permission=] with |descriptor| and |status|.
         1. If |status|' {{PermissionStatus/state}} is {{PermissionState/"denied"}} run the following steps:
             1. [=Reject=] |promise| with a "{{NotSupportedError}}" {{DOMException}}.
             1. If |immersive| is <code>true</code>, set [=pending immersive session=] to <code>false</code>.
             1. Abort these steps.
+        1. Let |session| be a new {{XRSession}} object.
+        1. [=Initialize the session=] with |session|, |mode|, and |device|.
         1. Potentially set the [=active immersive session=] as follows:
             <dl class="switch">
               <dt> If |immersive| is <code>true</code>