GitLab

Allow pull-to-refresh activation when the overscroll glow effect is
active but mostly transparent. This accomodates accidental refresh
prevention while easing the frustration of having to wait until
the overscroll glow has completely faded.

BUG=428429

Review URL: https://codereview.chromium.org/993613007

Cr-Commit-Position: refs/heads/master@{#320986}