Version: 52 (I will get the exact sync point later)
OS: Linux

I saw some very strange behaviour while working on https://codereview.chromium.org/1983803002/ (see Patch Set 15 and earlier) where deleting some views (using RemoveAllChildren(true)) and then recreating the exact same child views resulted in all the children being invisible, some of the time.

Specifically, I modified SubtleNotificationView with the logic (simplified):

void SubtleNotificationView::SetText(const base::string16& text) {
  RemoveAllChildren(true);
  views::Label* label = new Label(text);
  AddChildView(label);
}

I found that:
- If I call SetText with the exact same string every time, it's fine. It just looks like nothing changed.
- If I call SetText with different text to last time, it's fine; it changes to the new text.
- BUT, once I have called SetText with two different texts, from now on, whenever I call SetText with the same string as last time, all the content is invisible.
- The content becomes visible again upon changing the text.

It doesn't matter if I'm just creating a single label, or a whole Views hierarchy in there (e.g., SubtleNotificationView creates multiple labels in a BoxLayout with borders). All of the contents goes invisible. I've stripped down the code to deleting and recreating a single Label, as shown above, and it still happens.

This is baffling because I am not doing any special cases in my code that check for whether the string is the same. I don't know why Views would behave any differently based on the contents of the string matching against the contents of a previous Label that has been previously deleted. No idea, but it warrants further investigation.

In the mean time, I am working around this in Patch Set 16 of that CL by simply checking whether the string is the same, and taking no action in that case (which is good to do anyway).