Bug 507062 - Fix black strip of color in JavaDocHover (patch 2)

Use information colors api in JFaceColor instead of those in workbench.
This makes the Javadoc dialogue's strip at the bottom have the same
consistent color with all other dialogues in
eclipse. (e.g same as in code completion in ctrl+space).

See screenshot 'patch 2' in bug report.

Tests:
- Gtk: Javadoc hover, strip at the bottom looks like regular part of
Eclipse.
- Looks consistent on Dark and Light theme.
- Win/Cocoa: Javadoc hover, strip at the bottom looks same as before.

Note: The previous patch introduced ability to customize colour of this
strip at the bottom. But this made it inconsistent with other eclipse
dialogues like code-completion etc. This patch reverts customization in
favour of keeping things simple and working.

Patchset 4:
- Removed null check as api never returns null.

Change-Id: Ia6ebf0066b6f241675b2bcbac4c29824270f3415
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=507062 
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>
1 file changed