Remove intermediary RenderTaskDAG class

This thing is a leaky abstraction ("rawRemove" fn) and it doesn't
actually do much encapsulation. Almost all the code is just views into
the underlying array and wrappers that could be replaced by

std::algorithm routines (and in this CL, are). It's more trouble than
it's worth – maybe in the past that wasn't so.
Change-Id: I81f3aa6874525f8f2ed1315f50e084030e34865e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/332718
Commit-Queue: Adlai Holler <adlai@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
2 files changed