Move StyleBuilderConverter::ConvertValueToNumber to FilterOperationResolver

This function has a very generic name, but not a wide enough use case to
match. Move it to FilterOperationResolver, where its only two callers
are. Rename to something less generic.

Change-Id: Ibe6eaf68fbeddd86464d508cba3d6b235117f780
Reviewed-on: https://chromium-review.googlesource.com/c/1348096
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#610474}
3 files changed