Revert "focus exported color apis"

This reverts commit c5de102ff4b86b2f0facc011c1f47daa0fa68e97.

Reason for revert: SkColor4f::FromColor() is used by Chromium too.

Original change's description:
> focus exported color apis
> 
> Change-Id: I97f9db61698b6fee783fa3d6bfbbdd023fd6fee5
> Reviewed-on: https://skia-review.googlesource.com/156245
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Mike Klein <mtklein@google.com>

TBR=mtklein@google.com,bungeman@google.com,brianosman@google.com,reed@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: Ib8479e8d5ac9e124358188b1f58d3100613312fb
Reviewed-on: https://skia-review.googlesource.com/156362
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed