[MD] Always paint menu checks and arrows the same color, regardless of hover state.
[MD] Always paint menu checks and arrows the same color, regardless of
hover state.

Longer term, the raster assets should be removed in favor of vectorized
assets.

BUG=561133

Review URL: https://codereview.chromium.org/1481453002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#361772}

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