Bug 261662 - interface IEntityStyleProvider pulls in dependency on org.eclipse.ui.workbench

[ptziegler]

Based on https://bugs.eclipse.org/bugs/show_bug.cgi?id=261662.

Build ID: GEF-zest-sdk-3.5.0M4

Steps To Reproduce:
Download Zest examples, disable dependency to org.eclipse.ui.workbench and run any of the JFace snippets. They will fail with a NoClassDefFoundError, because of missing dependency to IDisposable:

java.lang.NoClassDefFoundError: org/eclipse/ui/services/IDisposable

IEntityStyleProvider is used e.g. in class GraphItemStyler, which in turn is used in class AbstractStylingModelFactory.

More information:
I would like to use Zest in a pure SWT/JFace or even Swing application, which should be possible, as there are working examples even in Zest source code (ok, the SimpleSWTExample needs org.eclipse.core.commands and org.eclipse.equinox.common, but that is just the example). When using JFace viewers, IEntityStyleProvider pulls in a dependency on org.eclipse.ui.services.IDisposable, which is contained in plugin/jar org.eclipse.ui.workbench_.jar. Requiring 4MB of code for a single interface qualifies as a bug in may opinion...

[ptziegler]

This means Zest can't be used in a pure E4 environment. Note that removing the IDisposable interface breaks API, so we'd have to do so when updating Zest Core to 2.0