The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/44e01ce042493dbc6289e0d148b6bcc6f258e537

commit 44e01ce042493dbc6289e0d148b6bcc6f258e537
Author: Eric Karl <ericrk@chromium.org>
Date: Fri Jan 05 19:09:14 2018

Wait for interactability in loadUrl* Android test helpers

Currently, when Chrome Android tests load a URL, they wait for the page
load event as well as instrumentation idle sync. At this point, many
tests immediately start interacting with the page. Unfortunately, this
doesn't guarantee page interactability, as Android waits for any layout
animations to complete before a tab becomes interactive. This can lead
to timing issues (as experienced in
https://chromium-review.googlesource.com/c/chromium/src/+/832959/24).

This change adds a new call, ChromeTabUtils.waitForInteractable, which
ensures that the tab is in a state where it can receive interactions.
The loadUrl* functions are updated to wait for this signal before
returning.

Bug:  799256 
Change-Id: I1fa92dc825e13f13a6273311a215064a7cb5b3ef
Reviewed-on: https://chromium-review.googlesource.com/851335
Commit-Queue: Eric Karl <ericrk@chromium.org>
Reviewed-by: Maria Khomenko <mariakhomenko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527339}
[modify] https://crrev.com/44e01ce042493dbc6289e0d148b6bcc6f258e537/chrome/test/android/javatests/src/org/chromium/chrome/test/ChromeActivityTestRule.java
[modify] https://crrev.com/44e01ce042493dbc6289e0d148b6bcc6f258e537/chrome/test/android/javatests/src/org/chromium/chrome/test/util/ChromeTabUtils.java