color: Remove flags for true color rendering

This is having too many complicated interactions with color correct
rendering and rasterization, and can be re-added (probably in a slightly
different form) once color correct render is on by default.

R=esprehn
TBR=achuith (for chrome/browser/chromeos/login)
BUG=667433
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2755583003
Cr-Commit-Position: refs/heads/master@{#456969}
15 files changed