Some tests use window.open() and then run things that need the compositor to function properly, e.g. off main thread animations. We need to give background sessions a Surface for this to work.

Comment on attachment 8984604 [details] Bug 1467915 - Connect a display to background windows in TestRunnerActivity https://reviewboard.mozilla.org/r/250476/#review256934 ::: mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/TestRunnerActivity.java:121 (Diff revision 1) > + session.acquireDisplay().surfaceChanged(surface, mView.getWidth(), mView.getHeight()); > + return session; > + } > + > + private void closeSession(GeckoSession session) { > + session.acquireDisplay().surfaceDestroyed(); Should be calling `releaseDisplay` instead of `acquireDisplay`. ::: mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/TestRunnerActivity.java:121 (Diff revision 1) > + session.acquireDisplay().surfaceChanged(surface, mView.getWidth(), mView.getHeight()); > + return session; > + } > + > + private void closeSession(GeckoSession session) { > + session.acquireDisplay().surfaceDestroyed(); Should be calling `releaseDisplay` instead of `acquireDisplay`.

Comment on attachment 8984604 [details] Bug 1467915 - Connect a display to background windows in TestRunnerActivity https://reviewboard.mozilla.org/r/250476/#review260416 ::: mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/TestRunnerActivity.java:115 (Diff revision 2) > final GeckoSession session = new GeckoSession(settings); > session.setNavigationDelegate(mNavigationDelegate); > return session; > } > > + private GeckoSession createBackgroundSession(GeckoSessionSettings settings) { final.

Pushed by jwillcox@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/3820ad4c882b Connect a display to background windows in TestRunnerActivity r=esawin