The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21

commit f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21
Author: Ryan Landay <rlanday@chromium.org>
Date: Wed Nov 22 22:17:15 2017

Allow IME dpad key events to move focus out of a WebView

WebView currently supports dpad keydown events moving focus out of a WebView
(e.g. to support things like the Nexus Player remote). However, we do not
currently support this properly if the dpad events come in through an open
InputConnection (vs. being dispatched directly to the view). TextView *does*
support this, so I'm fixing WebView in this CL to match TextView's behavior.

The issue is that Blink handles the dpad events differently depending on whether
something called spatial navigation mode is enabled. Dispatching a dpad event to
WebView enables it, and touch events disables it. I'm not intimately familiar
with the details of spatial navigation mode and am not sure if it's still
necessary or if we could do some refactoring in Blink to get rid of it.

This CL takes a conservative approach and just wires up ImeAdapter to notify
AwContents of dpad events so we can enable spatial navigation mode in this case.

Bug:  787651 
Change-Id: Ib4d0479ee75db8b53b990715b4f6a662fc0e52ec

TBR=tedchoc@chromium.org

Change-Id: Ib4d0479ee75db8b53b990715b4f6a662fc0e52ec
Reviewed-on: https://chromium-review.googlesource.com/784123
Commit-Queue: Ryan Landay <rlanday@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Changwan Ryu <changwan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518770}
[modify] https://crrev.com/f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21/android_webview/java/src/org/chromium/android_webview/AwContents.java
[modify] https://crrev.com/f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21/android_webview/javatests/src/org/chromium/android_webview/test/AwImeTest.java
[modify] https://crrev.com/f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
[modify] https://crrev.com/f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
[modify] https://crrev.com/f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21/content/public/android/java/src/org/chromium/content/browser/input/ImeAdapter.java
[modify] https://crrev.com/f7c6aed9e1b358f66f60f2965a2348c6b9b4ad21/content/public/android/java/src/org/chromium/content_public/browser/ImeEventObserver.java

Will be fixed in M64

1.Verified on Samsung Galaxy S7 Edge (SM-G935T)/ NRD90M having 64.0.3281.0 with Email version :4.1.83.3 and keyboard:1.5.86  ,Down to Up swipe was moving the cursor to the previous tab ( Subject field) BUT 
2.Not Verifiable on Samsung Galaxy J7 (SM-J710MN) / NRD90M having 64.0.3281.0 with Email version :4.1.82.0 and keyboard:2.0.21.30 and Cursor not moving to Subject field on swipe down to up ( Please clarify if this is intended).Thanks

sbashyam@, you're saying the fix isn't working on the J7?

Does using Cursor Control to move between the To and Subject fields work?

Mistake in Comment #5 observation 2.
Verifiable on Samusng Galaxy J7 /NRD90M  .My bad was using google keyboard in the initial observation . While using Samsung Keyboard, Issue no longer observed on 64.0.3281.0