Sluggish scrolling when accessibility is enabled on Android

[Roger00]

When any of the accessibility services is turned on,
the scrolling becomes sluggish.

• Device: Nexus 5X
• OS: Android 8.0.0, Build number OPP4.170623.014
• Chrome version: 59.0.3071.125 (stable)

Reproduce steps:

1. Enter system settings > accessibility
2. Enable any one of the services
3. Use chrome to view fixed-data-table

Several AccessibilityHostMsg_Events calls seems to block UI thread in the systrace log.

trace_fb_accessibility_on.zip