Text selection: fix snapping to words when words break across lines

Some languages do break words across lines and words can break between
lines with hyphenation. If a word has only one character on the current
line with the rest of the characters on the next line, the user would
be unable to move the cursor to the end of the word.

Rather than judging if a user is far enough into a word by using the
full word length, this CL amends the logic to only use the characters
that are on the current line of the word, if the user is far enough into
these characters the handle jumps to the next line to the end of the
word position.

Bug: 21400624
Change-Id: I8b96eb83bea08d9794d1e9db74066bcc3e168ac0