Add optional automatic PicCap handover for non-secure playback

tests/remote-navigation.test.js

@@ -4,8 +4,8 @@ const path=require('path');
 const vm=require('vm');
 const handlers={},windowHandlers={};
 const doc={activeElement:null,addEventListener(type,handler){handlers[type]=handler;}};
-const buttons=['start','stop','refresh','autostart'].map(id=>({
- id,disabled:false,clicks:0,handlers:{},
+const buttons=['start','stop','refresh','autostart','handover'].map(id=>({
+ id,disabled:id==='handover',clicks:0,handlers:{},
  addEventListener(type,handler){this.handlers[type]=handler;},
  focus(){doc.activeElement=this;this.handlers.focus();},
  click(){this.clicks++;}
@@ -25,5 +25,7 @@ doc.activeElement=null;key(39);assert.equal(doc.activeElement.id,'refresh');
 assert(!key(461));assert(!key(65));
 key(40);assert.equal(doc.activeElement.id,'autostart');key(38);assert.equal(doc.activeElement.id,'refresh');
 key(13);windowHandlers.blur();key(13);assert.equal(buttons[2].clicks,4);
+buttons[4].disabled=false;buttons[3].focus();key(39);assert.equal(doc.activeElement.id,'handover');
+key(39);assert.equal(doc.activeElement.id,'start');key(37);assert.equal(doc.activeElement.id,'handover');
 buttons.forEach(button=>button.disabled=true);assert(key(39));
 console.log('PASS: arrow navigation, wraparound, disabled controls, OK once per press, pointer handoff, focus recovery, Back preserved');