Replace Makefile with Android.bp.
Remove duplication of protos in proto directory.
Since we are now building the metrics_dump tool
under Android, use frameworks metrics.proto
directly. Also, reference cdm's wv_metrics.proto
from the cdm directory instead of creating a
subset in proto directory.
bug: 161783052
bug: 170607430
Test: build
m -j128 metrics_dump
Test: metrics_dump [bugreport from adt-3-r.zip]
Test: metrics_dump [bugreport from sabrina-q.gz]
Test: metrics_dump --widevine [adb shell dumpsys media.metrics output]
Change-Id: I82c7e723453ac2a6335cb2bb732a376d535b9ea3