Switch filament and backend to Abseil logging

[bejado]

This switches everything under filament/ to Abseil logging. The following mapping between utils::slog and Abseil severity is used:

slog.d  ->  DLOG(INFO)
slog.i  ->  LOG(INFO)
slog.v  ->  LOG(INFO)
slog.w  ->  LOG(WARNING)
slog.e  ->  LOG(ERROR)

[pixelflinger]

Will you be able to check how this affect the binary size on a release build?

[bejado]

Will you be able to check how this affect the binary size on a release build?

Yes, I'm planning on check that. Unfortunately I think Abseil log uses std iostream, so we may see a binary size increase.

[poweifeng]

I wonder if this should be a utils/std::stream, and then output to LOG(ERROR) at the end.

[bejado]

Yeah, I thought about that. The difference is that with LOG(ERROR), Abseil prepends metadata for each line. I guess we have to decide which style we prefer.

[bejado]

Unfortunately with Abseil, I'm seeing a 1.23 MiB binary size increase on Android. I'll need to investigate this some more to see what's going on. I was previously comparing main to an older branch which was skewing the results.

I'm seeing a 208.84 KiB binary size increase on Android.

jni/arm64-v8a/libfilament-jni.so:

Configuration	Size (bytes)
Before Abseil	3459984
With Abseil	3673832