This is a copy/paste from `addCompileSourceArtifacts` from `AbstractGwtShellMojo`. Could it be refactored instead of being copied? If the `compileSourcesArtifacts` are always added to the classpath, is `addCompileSourceArtifacts` still needed to begin with?
How about overriding `getProjectArtifacts` instead?
And how about caching the result of the computation into a field? (not sure it's needed though, those methods might only be called once per mojo)