Bug 515972: Javadoc hover shows mix of Info and Javadoc colors

Part 1:
For the HoverControl used by Javadoc hover, set Statusbar colors when
foreground/background is set (but only if statusBar is used).

Note:
- StatusbarLabel isn't always created, sometimes it's not used. We guard
against that with null-check.
- StatusBarLabel foreground is a blend of background and foreground, to
make it slightly 'lighter' than the main foreground. To account for
that, we re-blend when we either do background or foreground change.
Since color is created, it's lifecycle is treated carefully such that
we have no memory leaks.

Tests:
- With this patch alone, you won't see any changes. You need to apply
"Part 2" patch for javadoc to see changes to Javadoc. (See bug)
- Tested with child eclipse. No breakage for various popups like
  - Javadoc hover
  - jdt.debug.ui's expression viewer
  - editor markers
  - Problem info hover

This patch should be good for merging.

Change-Id: I6b13e06bbb27f49f28a56c4c05d65c2c65c150da
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>
1 file changed