This is intended (at least on trunk).

To clarify:
- in multi-line text fields (i.e. text areas and content editables), Search now gets used in the same way as Chrome OS's default mappings
- examples: Search+RIght invokes "end", Search+Ctrl+Right = control+end, etc
- single lined text fields are unaffected
- this new mapping also applies to Google Docs

To get out of the multi line text field, you can switch on sticky mode.

I'll use this bug to track the work to detect when the caret is on the beginning or end of the multi line and exit appropriately:
- Search+Up/Down: exits if the current range has no directed next text node
- Search+Left/RIght: exits if the current range has no directed next text *and* has caret position at the directed end of the text for the range

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/412557fc894544b0b9fa231e7f5d5f6451944fd8

commit 412557fc894544b0b9fa231e7f5d5f6451944fd8
Author: David Tseng <dtseng@chromium.org>
Date: Thu Mar 01 09:11:20 2018

Implement smart bounded text navigation

Currently:
- in multi-line text fields (i.e. text areas and content editables), Search now gets used in the same way as Chrome OS's default mappings
- examples: Search+RIght invokes "end", Search+Ctrl+Right = control+end, etc
- single lined text fields are unaffected
- this new mapping also applies to Google Docs

After this change:
- search+up/down, search+left/right will exit the editable if selection is on the first or last line of the editable (respectively)

Bug:  801590 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I991eb74d77120b2f2479a78b1b1658b31f354d85
Reviewed-on: https://chromium-review.googlesource.com/895244
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540112}
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/chromeos/accessibility/spoken_feedback_browsertest.cc
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/BUILD.gn
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/chromevox/background/kbexplorer.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs
[add] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/braille_command_data.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/braille_command_handler.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/chromevox_state.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/command_handler.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/cursors.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/desktop_automation_handler.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/editing.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/cvox2/background/panel.js
[modify] https://crrev.com/412557fc894544b0b9fa231e7f5d5f6451944fd8/chrome/browser/resources/chromeos/chromevox/testing/mock_feedback.js