The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/95935c3399729699905544ffea7f9cedc96315b0

commit 95935c3399729699905544ffea7f9cedc96315b0
Author: Tao Bai <michaelbai@chromium.org>
Date: Tue Nov 27 19:56:14 2018

Show AUTOFILL in the overflow menu

To be consistent with Android native view, this patch make WebView always show AUTOFILL menun in the overflow menu.

Bug:  907698 
Change-Id: Ibe9e8bfd3850177339cfd969488649b44b5524d5
Reviewed-on: https://chromium-review.googlesource.com/c/1347000
Commit-Queue: Tao Bai <michaelbai@chromium.org>
Reviewed-by: Changwan Ryu <changwan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611267}
[modify] https://crrev.com/95935c3399729699905544ffea7f9cedc96315b0/android_webview/java/src/org/chromium/android_webview/AutofillActionModeCallback.java

Verified on Nexus 6P/OPM1.180608.001, Long press on text fields invoking autofill shows the overfill menu on Long press in the email input fields .Tested Spotify/8.4.82.664 and Facebook/199.0.0.56.98 having Monochrome versions 72.0.3626.6 and 73.0.3630.0 .

Please confirm 
a.Long press on Input fields for auto fill is mandatory to invoke the over flow menu.
b.In facebook, Long press invokes the menu without displaying autofill, displaying user login automatically without me to tap the autofill from the overflow menu.

@michaelbai@ Please check the Video & bugreport attached =.  http://go/chrome-androidlogs1/8/907698 if behaviour mentioned in comment #4 is expected .Please confirm.Thanks