[GEF] Remove getter for absolute coordinates from Tool

All GEF classes are supposed to work with relative coordinates, which
can be translated to absolute coordinates, if necessary. However,
WindowBuilder initially only used absolute coordinates for everything.

With this removal, both projects now use the same coordinate system,
which allows us to use the GEF classes directly.

This change not only removes the `getAbsoluteStartLocation()` and
`getAbsoluteLocation()` methods from the `Tool` class, it also removes
the getter for the X and Y offset in the `IEditPartViewer` interface.

Author: ptziegler

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/IEditPartViewer.java

@@ -87,16 +87,6 @@ public interface IEditPartViewer extends ISelectionProvider, org.eclipse.gef.Edi
 	//
 	////////////////////////////////////////////////////////////////////////////
 
-	/**
-	 * @return viewer horizontal scroll offset.
-	 */
-	int getHOffset();
-
-	/**
-	 * @return viewer vertical scroll offset.
-	 */
-	int getVOffset();
-
 	/**
 	 * Returns the {@link EditDomain EditDomain} to which this viewer belongs.
 	 */

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/tools/Tool.java

@@ -242,8 +242,8 @@ private void setEvent(MouseEvent event) {
 
 	protected boolean movedPastThreshold() {
 		if (!getFlag(FLAG_PAST_THRESHOLD)) {
-			Point start = getAbsoluteStartLocation();
-			Point end = getAbsoluteLocation();
+			Point start = getStartLocation();
+			Point end = getLocation();
 			setFlag(FLAG_PAST_THRESHOLD, Math.abs(start.x - end.x) > DRAG_THRESHOLD || Math.abs(start.y - end.y) > DRAG_THRESHOLD);
 		}
 		return getFlag(FLAG_PAST_THRESHOLD);
@@ -348,23 +348,6 @@ public void viewerExited(MouseEvent event, EditPartViewer viewer) {
 	// Drop Access
 	//
 	////////////////////////////////////////////////////////////////////////////
-	/**
-	 * Returns the current x, y <b>*absolute*</b> position of the mouse cursor.
-	 */
-	public final Point getAbsoluteLocation() {
-		return new Point(getLocation().x + getCurrentViewer().getHOffset(),
-				getLocation().y + getCurrentViewer().getVOffset());
-	}
-
-	/**
-	 * Returns the starting mouse <b>*absolute*</b> location for the current tool operation. This is
-	 * typically the mouse location where the user first pressed a mouse button. This is important for
-	 * tools that interpret mouse drags.
-	 */
-	protected Point getAbsoluteStartLocation() {
-		return new Point(getStartLocation().x + getCurrentViewer().getHOffset(),
-				getStartLocation().y + getCurrentViewer().getVOffset());
-	}
 
 	/**
 	 * Resets all state fields to default values.

org.eclipse.wb.core/src-gef/org/eclipse/wb/internal/gef/graphical/GraphicalViewer.java

@@ -83,22 +83,6 @@ public FigureCanvas getControl() {
 		return m_canvas;
 	}
 
-	/**
-	 * @return viewer horizontal scroll offset.
-	 */
-	@Override
-	public int getHOffset() {
-		return m_canvas.getViewport().getHorizontalRangeModel().getValue();
-	}
-
-	/**
-	 * @return viewer vertical scroll offset.
-	 */
-	@Override
-	public int getVOffset() {
-		return m_canvas.getViewport().getVerticalRangeModel().getValue();
-	}
-
 	/**
 	 * Returns root {@link EditPart}.
 	 */

org.eclipse.wb.core/src-gef/org/eclipse/wb/internal/gef/tree/TreeViewer.java

@@ -73,22 +73,6 @@ public Tree getControl() {
 		return m_tree;
 	}
 
-	/**
-	 * @return viewer horizontal scroll offset.
-	 */
-	@Override
-	public int getHOffset() {
-		return 0;
-	}
-
-	/**
-	 * @return viewer vertical scroll offset.
-	 */
-	@Override
-	public int getVOffset() {
-		return 0;
-	}
-
 	/**
 	 * Returns root {@link EditPart}.
 	 */

org.eclipse.wb.tests/src/org/eclipse/wb/tests/gef/EmptyEditPartViewer.java

@@ -123,16 +123,6 @@ public void removeSelectionChangedListener(ISelectionChangedListener listener) {
 	public void setSelection(ISelection selection) {
 	}
 
-	@Override
-	public int getHOffset() {
-		return 0;
-	}
-
-	@Override
-	public int getVOffset() {
-		return 0;
-	}
-
 	@Override
 	public RootEditPart getRootEditPart() {
 		return null;