LatencyInfo: enable async event reporting for both latencyInfo and benchmark categories

This fixes initializer for benchmark_enabled to actually check for both benchmark and
latencyInfo to match the categories actually used in trace events and renames it to
latency_info_enabled.

BUG=520659

Review URL: https://codereview.chromium.org/1462923003

Cr-Commit-Position: refs/heads/master@{#361172}
1 file changed