DO NOT MERGE. Fix logic for switching between overscroll and scroll modes.

The issue here was originally that webview was showing twice
as intense of an effect for edge glow as lists. The root cause
was that abslistview was calling onPull half as often as webview. This
occurred because every time an action_move came into the touch handler
for abslistview when it was in overscroll, the mode was ALWAYS changed
back to scroll mode. Therefore, half the action_move events were
essentially being eating by the abslistview state machine.
After fixing that issue, needed to decrease the intensity of the effect
for webview and abslistview by halving the PULL_DISTANCE_GLOW_FACTOR.

Change-Id: I5dbdf4f1219f3bb157a71d4fccf8fa42e2abe047