Add GetMinimumSize() for Labels and ensure it's zero for empty Links.

Add GetMinimumSize() for Labels and ensure it's zero for empty Links.

This requires auto-disabling focusability for empty links.  I also reordered the
overrides for Link to match the View declaration order.

This also requires some major reworking of StyledLabel, which previously assumed
all Links had a focus border, and to make layout easier just forced space for a
focus border on all children at all times, as well as always reserving space
itself.  I've changed this so StyledLabel lays out children correctly,
accounting for their focus borders, and only adds space for one itself if any
children have a focus border.  This eliminates the need for
Label::SetHasFocusBorder(), which only had one non-StyledLabel caller (who
didn't need it).

BUG=none
TEST=none
R=sky@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=239864

[Peter Kasting, 2013-12-10 07:30:26]

I had to update this to fix the unittests, which required major surgery to
StyledLabel.  On the plus side, StyledLabel won't waste space for a focus border
when it doesn't need one now.  See updated CL description for more details.

[Peter Kasting, 2013-12-10 07:32:29]

Oh, I should note.  I changed StyledLabel from a priority queue for ranges to a
sorted list.  Because the only times we wanted to consume the priority queue we
really wanted to iterate through the whole thing, we were really treating it as
a sorted container anyway, just a less-efficient one that you had to copy before
examining.  Lame.

[sky, 2013-12-10 17:18:00]

https://codereview.chromium.org/111023004/diff/40001/ui/views/controls/label.cc
File ui/views/controls/label.cc (right):

https://codereview.chromium.org/111023004/diff/40001/ui/views/controls/label....
ui/views/controls/label.cc:205: if (IsFocusable()) {
Why do you want IsFocusable() here rather than focusable_? One potential bad
thing about IsFocusable() is that it uses IsDrawn, which means the return value
changes once added to a Widget. I tend to think you only care about focusable_
here.

https://codereview.chromium.org/111023004/diff/40001/ui/views/controls/styled...
File ui/views/controls/styled_label.cc (right):

https://codereview.chromium.org/111023004/diff/40001/ui/views/controls/styled...
ui/views/controls/styled_label.cc:135: is_drawn_ = IsDrawn();
Similar to my comment in Label I think you should not worry about IsDrawn and
always do this.

[Peter Kasting, 2013-12-10 18:59:31]

OK, removed all the IsFocusable()-related changes, PTAL.

[sky, 2013-12-10 21:07:09]

LGTM

[Peter Kasting, 2013-12-10 22:18:44]

Committed patchset #5 manually as r239864 (presubmit successful).