Gradients are now an absurd Chimera

As of O, gradients are interpolated in linear space. This unfortunately
affects applications that were expecting a certain behavior for the
alpha ramp. This change attempts to get the best of both world: better
color interpolation (in linear space) and the old alpha interpolation
(in gamma space). This is achieved by applying the electro-optical
transfer function to the alpha channel; an idea so wrong it would
make any graphics programmer worth his salt weep in disgust.

As abhorrent this idea might be to me, it also acts as a faint
beacon of hope admist the unfathomable darkness that is Android's
color management.

And if you allow me another misguided metaphor, this change
represents the flotsam I can cling onto in the hope to one day
reach the bountiful shores of linear blending and accurate color
management. Would this change not fix the distress caused by its
predecessors, I will have no choice but bow my head in shame until
the day I can finally devise an infallible plan.

Bug: 33010587
Test: CtsUiRenderingTestCases
Change-Id: I5397fefd7944413f2c820e613a5cba50579d4dd5