[eclipse-pmc] API request: contract change to enable reusing ViewerRow o

[Boris Bokowski <Boris_Bokowski@xxxxxxxxxx>]

We would like to request permission
for a contract change on API introduced in 3.3, and one additional API
method.  With the current contract, implementations cannot re-use
ViewerRow objects even though they are (in most cases) only used locally.
 The additional API method can be used to clone a ViewerRow object
should it be used non-locally.

GOALS/BENEFITS:
More opportunities for optimization.

CORRESPONDING BUG:
Bug 174701 [Viewers] ViewerRow should
be reused instead of connected to the Item, https://bugs.eclipse.org/bugs/show_bug.cgi?id=174701

RISKS:
Minimal risk.  This will very likely
only affect subclasses of ColumnViewer that have stepped up to using the
new API in 3.3.  Nebula contains the only known subclass outside of
JFace.

PERFORMANCE IMPACT:
Instead of allocating one object plus
one array per item, we only allocate one object per tree or table.

Thanks,
Boris.