[Android] StageWebView doesn't work with <runtimeInBackgroundThread>true</runtimeInBackgroundThread>

[itlancer]

Problem Description

StageWebView doesn't work with <runtimeInBackgroundThread>true</runtimeInBackgroundThread> for Android.
Webframe just doesn't show.

Tested with latest AIR 50.2.2.3 and AIR 50.2.2.4 versions with multiple different Android devices with different OS versions with different applications and architectures.
Same problem in all cases.
There is no such problem without <runtimeInBackgroundThread>true</runtimeInBackgroundThread>.

Related issue:
#2615

Steps to Reproduce

Launch application with code below. It just display StageWebView.

Application example with sources attached.
android_runtimeinbackgroundthread_stagewebview_bug.zip

package {
	import flash.display.Sprite;
	import flash.geom.Rectangle;
	import flash.media.StageWebView;
	import flash.events.Event;
	
	public class AndroidRuntimeInBackgroundThreadStageWebViewBug extends Sprite {
		private var stageWebView:StageWebView;
		
		public function AndroidRuntimeInBackgroundThreadStageWebViewBug() {
			addEventListener(Event.ADDED_TO_STAGE, init);
		}
		
		private function init(e:Event):void {
			removeEventListener(Event.ADDED_TO_STAGE, init);
			
			stageWebView = new StageWebView(true);
			stageWebView.loadURL("https://airsdk.harman.com/");
			stageWebView.viewPort = new Rectangle(0, 100, 1280, 620);
			stageWebView.stage = stage;
		}
	}
}

Actual Result:
StageWebView not displayed.
With ADB Logcat you can see error log:

W/System.err: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
W/System.err:     at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:9629)
W/System.err:     at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:1919)
W/System.err:     at android.view.View.requestLayout(View.java:26296)
W/System.err:     at android.view.View.requestLayout(View.java:26296)
W/System.err:     at android.view.View.requestLayout(View.java:26296)
W/System.err:     at android.view.View.requestLayout(View.java:26296)
W/System.err:     at android.view.ViewGroup.addView(ViewGroup.java:5075)
W/System.err:     at android.view.ViewGroup.addView(ViewGroup.java:5017)
W/System.err:     at android.view.ViewGroup.addView(ViewGroup.java:4989)
W/System.err:     at com.adobe.air.AndroidActivityWrapper.getOverlaysLayout(AndroidActivityWrapper.java:781)
W/System.err:     at com.adobe.air.AndroidWebView.addedToStage(AndroidWebView.java:731)
W/System.err:     at com.adobe.air.Entrypoints.EntryMainWrapper(Native Method)
W/System.err:     at com.adobe.air.Entrypoints.run(Entrypoints.java:275)
W/System.err:     at java.lang.Thread.run(Thread.java:1012)

Expected Result:
StageWebView will be shown.

Known Workarounds

none
*Do not use <runtimeInBackgroundThread>true</runtimeInBackgroundThread>.

[itlancer]

Fixed with latest AIR 50.2.2.6. Thanks!
But issue with StageText still exists #2615