Bug 52611 [QuickDiff] Let QuickDiff hovers adapt to horizontal scrollbar
Test Case: - on a long line: make a change such that you have to scroll horizontally to see the change - use QuickDiff -> Hover shows line from its start and does not match the horizontally scrolled text in the editor
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/JavaChangeHover.java
* Returns the partition type of the document displayed in <code>viewer</code> at <code>startLine</code>.
	 * @param viewer the viewer
	 * @param startLine the line in the viewer
	 * @return the partition type at the start of <code>startLine</code>, or <code>IDocument.DEFAULT_CONTENT_TYPE</code> if none can be detected
	 */
	private String getPartition(ISourceViewer viewer, int startLine) {
		if (viewer == null)
			return null;
		IDocument doc= viewer.getDocument();
		if (doc == null)
			return null;
		if (startLine <= 0)
			return IDocument.DEFAULT_CONTENT_TYPE;
		try {
			ITypedRegion region= TextUtilities.getPartition(doc, fPartitioning, doc.getLineOffset(startLine) - 1, true);
			return region.getType();
		} catch (BadLocationException e) {
		}
		return IDocument.DEFAULT_CONTENT_TYPE;
	}
	
	
	/*
	 * @see org.eclipse.jface.text.source.LineChangeHover#getTabReplacement()
	 */
	protected String getTabReplacement() {
		return Character.toString('\t');
	}
}