Switch to a simple #define instead of conditional build targets.
No one changes skia_enable_effects or skia_enable_effects_imagefilters,
so we can merge all that together back into :skia.
Change-Id: I2985f95ee89149ddc687dc31f4c6bf35cb3a93c7
Reviewed-on: https://skia-review.googlesource.com/c/169220
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
5bbf790b5b