surfaceflinger: generalize Description::mIsWideGamut

Generalize the mIsWideGamut bool into input and output transfer
functions.  In most cases, the transfer functions are LINEAR,
meaning EOTF() and OETF() are no-op.

Test: manual
Change-Id: I18bfa97ffa950190b553a2ebb18f68b72ab296dd
5 files changed