Revert "[Mac] Add Offset to TextSuggestionsTouchBarController Text Selection"

This reverts commit 1e3c17435eea13b5ba5d2794985655aa221091d1.

Reason for revert: Breaks Mac tests, see e.g. https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8938549477492727648/+/steps/browser_tests_on__none__GPU_on_Mac_on_Mac-10.11/0/logs/TextSuggestionsTouchBarControllerTest.Offset/0

Original change's description:
> [Mac] Add Offset to TextSuggestionsTouchBarController Text Selection
> 
> When the text surrounding the current selection gets too long, only
> part of it is received by TextSuggestionsTouchBarController. The
> location of the received text within the total block of text is
> denoted by an offset. Previously, TextSuggestionsTouchBarController
> did not take this offset into account, causing crashes when the
> selection range was past the end of the received text.
> 
> The offset is passed along with the text and selection range. The
> selection range within the received text is calculated using the
> offset and received selection range. The editing word range is stored
> both as the range within the received text and the range within the
> total text for checking when to ignore text selection updates.
> 
> RenderWidgetHostView::GetOffsetForSurroundingText() was added to
> retrieve the offset on WebContents update.
> 
> Browser tests were modified to account for the new offset parameter. A
> new browser test, TextSuggestionsTouchBarController.Offset, was added
> to test that the controller properly handles offsets.
> 
> Bug: 717553
> Change-Id: I6dce1405fd5c115ca6ddfdbe4157faf75ccc3a6c
> Reviewed-on: https://chromium-review.googlesource.com/1169597
> Commit-Queue: Tessa Nijssen <tnijssen@google.com>
> Reviewed-by: Avi Drissman <avi@chromium.org>
> Reviewed-by: Sarah Chan <spqchan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#582205}

TBR=avi@chromium.org,spqchan@chromium.org,tnijssen@google.com

Change-Id: If0acdd0494b5270c4b4e221e16b8e901ce2cacc3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 717553
Reviewed-on: https://chromium-review.googlesource.com/1171704
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582423}
13 files changed