servo/servo — pull request #2977 by mrobinson (2014-07-31 22:10:52+00:00)
Title: Make scrolling tick by device pixels

Instead of converting a device offset into a page offset and then
converting back when positioning layers, keep scroll offsets in device
pixels. We still do conversions when calculating the scroll offset for
pinch zoom, but we can remove those when pinch zoom and contents zoom
are fully separated.