Merge "Check if SC is valid before calling setTransparentRegionHint" into sc-dev

                    // via the WM relayout code path. We probably eventually

                    // want to synchronize transparent region hint changes

                    // with draws.

                    mTransaction.setTransparentRegionHint(getSurfaceControl(),

                        mTransparentRegion).apply();

                    SurfaceControl sc = getSurfaceControl();

                    if (sc.isValid()) {

                        mTransaction.setTransparentRegionHint(sc, mTransparentRegion).apply();

                    }

                }

            }