Make SelectionConverter resolve all highlighted IJavaElements

[amartya4256]

Issue: eclipse-jdt/eclipse.jdt.ui#1173

Current Situation

SelectionConverter can be used to highlight a piece of code and resolve it to get a context of all the IJavaElement in it. However, the method SelectionConverter.codeResolve returns an empty array if the highlighted section consists of more than one IJavaElement. This operation directly affects Self Encapsulate Fields and Create Getter and Setter operations, since the dialog opened for these operations should already have marked the highlighted fields .

Expected Behavior

SelectionConverter.codeResolve should return an array consisting of all the IJavaElement which are highlighted by the user.

Proposed Solution

TBD