It seems the magic done with the 4px margin and its calculations
are not really needed. Getting rid of this does not only clean
the code but is also very helpfull for the new slider logic.
Change-Id: Iae86b8024d3b56517bdc4db5e8baec69bd61afbf
Introducing a new class that draws lines between the pointers
and the related diff columns. Lines are redrawn when pointers
were moved. A colored border is added to the diff columns and
readded when the diff changes.
Bug: T149175
Change-Id: Iadf779368c58da7779c769bda8e9bd3fc5afcffa
