Merge "Don't destroy surfaces of activities launched behind early." into lmp-mr1-dev

        transformation.clear();

        final int N = mAllAppWinAnimators.size();

        for (int i=0; i<N; i++) {

            final WindowStateAnimator winAnim = mAllAppWinAnimators.get(i);

            if (mAppToken.mLaunchTaskBehind) {

                winAnim.mWin.mExiting = true;

            }

            winAnim.finishExit();

        final int numAllAppWinAnimators = mAllAppWinAnimators.size();

        for (int i = 0; i < numAllAppWinAnimators; i++) {

            mAllAppWinAnimators.get(i).finishExit();

        }

        if (mAppToken.mLaunchTaskBehind) {

            try {