[Graphite] Add query for resourceType to graphite Resources

The resourceType is returned to a caller using dumpMemoryStatistics to
know the type of resource we are reporting data on.

Bug: b/308774680
Change-Id: I7757a7a4b678bfba2111133a585612dbf677490b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/773416
Reviewed-by: Nicolette Prevost <nicolettep@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
13 files changed