Interface implemented by guarded block refactoring handlers. Contains a callback method
that gets a RefactoringElementImplementation affecting a guarded block as a parameter and can return
the new RefactoringElementImplementation that will replace the passed RefactoringElementImplementations
in the result collection of refactoring elements for a given refactoring.
Collects replacements for refactoring element affecting a guarded block.
proposedChange - RefactoringElementImplementation that affects a guarded block.
replacements - Empty collection where the method implementation should add the
replacement RefactoringElementImplementations if this GuardedBlockHandler can handle changes in the
guarded block the original RefactoringElementImplementation affects.
transaction - collection of Transactions.
Problems found or null (if no problems were identified)