The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/391725483f063ccd19c698785dd9dfb2e48c86ce

commit 391725483f063ccd19c698785dd9dfb2e48c86ce
Author: Laís Minchillo <laisminchillo@chromium.org>
Date: Wed Jan 02 18:38:53 2019

[aw] Post proxy override methods to the UI thread

Bug:  918350 
Change-Id: Ieac9c9e1590c4cfe8f39d9f9bdfd510b41be616e
Reviewed-on: https://chromium-review.googlesource.com/c/1392719
Reviewed-by: Tobias Sargeant <tobiasjs@chromium.org>
Commit-Queue: Laís Minchillo <laisminchillo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619438}
[modify] https://crrev.com/391725483f063ccd19c698785dd9dfb2e48c86ce/android_webview/java/src/org/chromium/android_webview/AwProxyController.java
[modify] https://crrev.com/391725483f063ccd19c698785dd9dfb2e48c86ce/android_webview/support_library/java/src/org/chromium/support_lib_glue/SupportLibProxyControllerAdapter.java
[modify] https://crrev.com/391725483f063ccd19c698785dd9dfb2e48c86ce/android_webview/support_library/java/src/org/chromium/support_lib_glue/SupportLibWebViewChromiumFactory.java

To manually verify this just run tests in AwProxyControllerTest