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

Review URL: https://codereview.chromium.org/108573007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242003 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242003
Swap the parameters to SendSwapCompositorFrameAck() so they match the function declaration.

BUG=none

Review URL: https://codereview.chromium.org/101503004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242004 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242004