Expand GPU rasterization trigger for field trial

This allows expanding the GPU rasterization trigger for
a field trial. The expanded trigger is
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BUG=380454

Review URL: https://codereview.chromium.org/309593007

git-svn-id: svn://svn.chromium.org/blink/trunk@175699 bbb929c8-8fbe-4397-9dbb-9b2b20218538