Revert "Changes AXSystemCaret bounds when the selection bounds change and not only when there is a text selection"

This reverts commit dac5704fcb205975526a851224860137c03f17d1.

Reason for revert: Reproducible crash introduced: crbug.com/786317

Original change's description:
> Changes AXSystemCaret bounds when the selection bounds change and not only when there is a text selection
>
> On Windows, we report the location and size of the caret to screen magnifiers so that they can track it.
> Until now, we were only updating the caret location when there was some text in the text field.
> However, if a text field or content editable has no text inside it and it's location on screen has changed, we were not updating the caret location because the caret inside it hasn't actually moved but its container has.
> R=​dmazzoni@chromium.org, kenrb@chromium.org
>
> Bug: 782843
> Change-Id: I56065da82067710f082ea788b60260d18cdd8706
> Tested: manually by moving an iframe with an empty content editable around and checking caret bounds
> Reviewed-on: https://chromium-review.googlesource.com/759161
> Commit-Queue: Nektarios Paisios <nektar@chromium.org>
> Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
> Reviewed-by: Ken Buchanan <kenrb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#516559}

TBR=aleventhal@chromium.org, dmazzoni@chromium.org, kenrb@chromium.org, mfoltz@chromium.org, nektar@chromium.org, sadrul@chromium.org


(cherry picked from commit 607ad24f9067a2eed21724b6d54005b8f00aeffe)

Bug: 782843,786317
Change-Id: Ia6cfb907fe65b9c78e7e8a1d1ec07b4cd9c03cab
Reviewed-on: https://chromium-review.googlesource.com/815459
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Commit-Queue: mark a. foltz <mfoltz@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#522594}
Reviewed-on: https://chromium-review.googlesource.com/833342
Cr-Commit-Position: refs/branch-heads/3282@{#282}
Cr-Branched-From: 5fdc0fab22ce7efd32532ee989b223fa12f8171e-refs/heads/master@{#520840}
2 files changed