private void maybeOnFadeFinished() {
    if (!mIsFadingActualImage) {
      return;
    }
    mIsFadingActualImage = false;

    if (mOnFadeListener != null) {
      mOnFadeListener.onFadeFinished();
    }
  }
Gets the transition state (STARTING, RUNNING, NONE). Useful for testing purposes.

@return transition state
drawee/src/main/java/com/facebook/drawee/drawable/FadeDrawable.java