GitLab

This deletes code that was previously used for deciding if the
expanded content whitelist for GPU rasterization should be used.
Blink now uses the expanded whitelist by default (that is,
WebSettings::setUseExpandedHeuristicsForGpuRasterization is
now a no-op), so this code is no longer needed.

BUG=404866

Review URL: https://codereview.chromium.org/496503002

Cr-Commit-Position: refs/heads/master@{#291744}