Previously, we did not scroll to target in the cursor manager if the top
was visible. However, there were times where the bottom content was
not visible, and it could have moved up into view.
This change passes an optional function for calcuating target height to
the cursor manager. If it is passed, the function is used to calculate
height instead of targetHeight. Height is ultimately used to determine
if the bottom is visible.
If the top is visible, but the bottom is not, scroll to the target if
the scroll position is farther down than the current position. Don't
scroll if the condition is not met because more content related to the
target is actually visible without scrolling, and do not want to reduce
it.
Bug: Issue 5498
Change-Id: I1708c921093b6e8b1916ae68fb468816f7c67633
ef950faaab