harden pathmeasure and fix empty case

change int to unsigned (just make it uniform,
part of it was already unsigned)

change path by pointer to path by value
since it will be copied on write; fixes bug
where path changes from underneath measure

Allow empty paths to still initialize measure state.
This fixes the GM failure from the earlier check-in attempt
in CL 113269.

R=reed@google.com
Bug: skia:7675
Change-Id: I6296bbf75296ead826e54662b025277dd226e2b8
Reviewed-on: https://skia-review.googlesource.com/113246
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
2 files changed