DO NOT MERGE Refactor find and select dialogs

DO NOT MERGE Refactor find and select dialogs

(Change imported by hand from master, based on
https://android-git.corp.google.com/g/#change,53489 )

SelectText now permits incremental extension of the selection
using either touch or trackball data. SelectText adds word selection
and select all interfaces.

SelectText has been rewritten to do a better job of finding space
characters and selecting text outside of the visible window.

Companion changes in frameworks/base and packages/apps/Browser

Change-Id: I28a815375345d842f79464edbf0cb3a2019b7fe8
http://b/2626451