Bug 73082 [Encoding] Need an encoding extension point
We need to have an extension point for encodings. All it need have is the IDs of the encodings that are to be added to the list. It will require verification and indication of unavailable encodings.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/IDEEditorsPreferencePage.java
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Group;
import org.eclipse.ui.WorkbenchEncoding;
import org.eclipse.ui.ide.IDEEncoding;
import org.eclipse.ui.internal.dialogs.EditorsPreferencePage;
import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
/**
 * Extends the Editors preference page with IDE-specific settings.
 *
 * Note: want IDE settings to appear in main Editors preference page (via subclassing),
 *   however the superclass, EditorsPreferencePage, is internal
 */
public class IDEEditorsPreferencePage extends EditorsPreferencePage {
    
    private String defaultEnc;
    
    
    private boolean clearUserSettings = false;
    private Button defaultEncodingButton;
    private Button otherEncodingButton;
    private Combo encodingCombo;
    protected Control createContents(Composite parent) {
        Composite composite = createComposite(parent);
        createEditorHistoryGroup(composite);
        createSpace(composite);
        createShowMultipleEditorTabsPref(composite);
        createCloseEditorsOnExitPref(composite);