add a basic profiling mode to src/Transform.c

Since we switched to the One Big Switch style, function-level
profiling isn't very helpful.  This dumps out a rough profile
broken down by Op.

Change-Id: I51c92ebe3c2337d3a287d41dc6d79db6309c5a02
Reviewed-on: https://skia-review.googlesource.com/121484
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
5 files changed