Changed the handle type from "bottom" to "top" when the handle go to the bottom of...

Changed the handle type from "bottom" to "top" when the handle go to the bottom of the visible webview area.

[Title] Changed the handle type from "bottom" to "top" when the handle go to the bottom of the visible webview area.
[Issue#] N_SE-40983
[Problem] If the handle go to the bottom of visible webview area,
          the handle is not selected well.
[Cause] The handle is truncated on the visible webview area.
[Solution] When the handle go to the bottom of the visible webview area,
           changed the handle type from "bottom" to "top".

Change-Id: I7557c7a1a02e169629d220966335bbc554321d53