Tentatively sending to Biao cause it could be focusing textbox triggering and I see https://chromium-review.googlesource.com/c/chromium/src/+/1050809 coming.

The problem is that navigate to a new page from "recent tabs" page changes the web_content which associated with current tab. When that happened, we should update the ImeAdapter which associated with the new web content and restore the ImeAdapter of the old web content. We currently don't do that. So the 2D keyboard shows up.
I need a little bit more time to figure out the relationship of tab and webcontent and tab switching. should have a CL to fix it soon.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/87a5c00489d3998a99f923388295b632eefd3c50

commit 87a5c00489d3998a99f923388295b632eefd3c50
Author: Biao She <bshe@chromium.org>
Date: Tue May 15 16:40:41 2018

Fix 2D virtual keyboard shows up after navigate from recent tabs in VR

This CL makes sure that a VR version ImeAdapter is used when WebContent
for current tab swapped.


Bug:  841607 
Change-Id: I751221684c17101ae80c4ebeff5684f5f5b7f8c5
Reviewed-on: https://chromium-review.googlesource.com/1057827
Reviewed-by: Amirhossein Simjour <asimjour@chromium.org>
Commit-Queue: Biao She <bshe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558745}
[modify] https://crrev.com/87a5c00489d3998a99f923388295b632eefd3c50/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/274d58bc9d2743c49d0edd23c084d82e3e244315

commit 274d58bc9d2743c49d0edd23c084d82e3e244315
Author: Biao She <bshe@chromium.org>
Date: Wed May 23 23:30:20 2018

Hide voice search button in VR if RecognizerIntent can't be resolved


Bug:  841607 
Change-Id: I936202dcf3b01459e7914f237b22d8c0e5b09137
Reviewed-on: https://chromium-review.googlesource.com/1070544
Commit-Queue: Biao She <bshe@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561309}
[modify] https://crrev.com/274d58bc9d2743c49d0edd23c084d82e3e244315/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java

The commit in #4 is not intented for this issue. I made a mistake. It is intended for Issue 842322.

commit in #3 should have fixed this issue. So mark it as closed.