ViewRootImpl.java

@Override
public ViewParent invalidateChildInParent(int[] location, Rect dirty) {
    checkThread();
    // ... Here goes the actual invalidation logic
}

void checkThread() {
    if (mThread != Thread.currentThread()) {
        throw new CalledFromWrongThreadException(
                "Only the original thread that created a view hierarchy can touch its views.");
    }
}