[518957] Reuse SemanticUMLContentProvider instance per resource set

The SemanticUMLContentProvider is working based on resource sets and its
instantiation is not cheap:
- Allow sharing of content providers
- Reuse content providers for all eObjects of the same resource set

Bug: 518957
Change-Id: I2070f145acbccd241cefe913fd6e18836d3e7560
Signed-off-by: Martin Fleck <mfleck@eclipsesource.com>
2 files changed