Use TextInputState to provide state of a text field.

RWHVA::{GetTextRange, GetTextFromRange} used
TextInputManager::TextSelection provided by TextInputManager which
includes texts outside of a text field.
This CL changes content getter methods of TextInputClient
interface to use TextInputState to avoid inconsistency caused by using
results of different IPCs.

Bug: 901439
Test: content_unittests
Change-Id: I3e5031eb03d6e96e281443cab4a8257053c39b7f
Reviewed-on: https://chromium-review.googlesource.com/c/1412092
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624718}
2 files changed