Bug 163360 [Field Assist] - API - Provide ControlDecoration constructor without specifying decoration
Currently you can only create a ControlDecoration by specifying the control and the decoration in the constructor. This works nicely when the decoration is static (ie, always content assist). But there are use cases where the decoration changes depending on the state of the field, and at creation time, it's not clear which decoration will be set. Having a constructor that doesn't require a decoration would be nice.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ControlDecoration.java
region.dispose();
			}
		}
		/*
		 * Set the visibility of the hover.
		 */
		void setVisible(boolean visible) {
			if (visible) {
				if (!hoverShell.isVisible()) {
					hoverShell.setVisible(true);
				}
			} else {
				if (hoverShell.isVisible()) {
					hoverShell.setVisible(false);
				}
			}
		}
		/*
		 * Set the text of the hover to the specified text. Recompute the size
		 * and location of the hover to hover near the decoration rectangle,
		 * pointing the arrow toward the target control.
		 */
		void setText(String t, Rectangle decorationRectangle,
				Control targetControl) {
			if (t == null) {
				t = EMPTY;
			}
			if (!t.equals(text)) {
				Point oldSize = getExtent();
				text = t;