Define cleanup of remote end state

Author: jgraham

index.bs

@@ -1435,10 +1435,23 @@ To <dfn>cleanup the session</dfn> given |session|:
 
 1. [=Close the WebSocket connections=] with |session|.
 
+1. If [=active sessions=] is [=list/empty=], [=cleanup remote end state=].
+
 1. Perform any implementation-specific cleanup steps.
 
 </div>
 
+<div algorithm>
+To <dfn>cleanup remote end state</dfn>.
+
+1. [=map/Clear=] the [=before request sent map=].
+
+1. Set the [=default cache bypass=] to false.
+
+1. [=set/Empty=] the [=navigable cache bypass set=].
+
+</div>
+
 <div algorithm>
 To <dfn>update the event map</dfn>, given
 |session|, |requested event names|, |browsing contexts|, and |enabled|:
@@ -2324,6 +2337,9 @@ BrowsingContextEvent = (
 A [=remote end=] has a <dfn>device pixel ratio overrides</dfn> which is a weak map
 between [=navigables=] and device pixel ratio overrides. It is initially empty.
 
+Note: this map is not cleared when the final session ends i.e. device pixel
+ratio overrides outlive any WebDriver session.
+
 ### Types ### {#module-browsingcontext-types}
 
 #### The browsingContext.BrowsingContext Type #### {#type-browsingContext-Browsingcontext}