The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/347b99eb0aa4ec48748e4dbe39f5ac0b9c8962f5

commit 347b99eb0aa4ec48748e4dbe39f5ac0b9c8962f5
Author: Shimi Zhang <ctzsm@chromium.org>
Date: Thu Feb 22 22:41:27 2018

[Android] Updates WindowAndroid for SelectionPopupControllerImpl

|SelectionPopupControllerImpl| is not updating its |WindowAndroid| when
reparenting the corresponding |Tab| to a different activity.

This CL let SelectionPopupControllerImpl implements
WindowAndroidChangedObserver, so it observes WindowAndroid change
from ContentViewCoreImpl.

Change-Id: I8b096fbe36e5924f8f60db409d1345c3fa35603c
Bug:  814927 
Reviewed-on: https://chromium-review.googlesource.com/932447
Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Shimi Zhang <ctzsm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538596}
[modify] https://crrev.com/347b99eb0aa4ec48748e4dbe39f5ac0b9c8962f5/content/public/android/java/src/org/chromium/content/browser/ContentViewCoreImpl.java
[modify] https://crrev.com/347b99eb0aa4ec48748e4dbe39f5ac0b9c8962f5/content/public/android/java/src/org/chromium/content/browser/selection/SelectionPopupControllerImpl.java