Fix some 64 bit warnings on mac.

SkAAClip:
Change fDataSize to a size_t, since that is how it is used in all
cases.

SkAlphaRuns.cpp:
Use SkToS32 when subtracting a pointer from another pointer to
return an int.

BUG=http://code.google.com/p/skia/issues/detail?id=1103

Review URL: https://codereview.appspot.com/7314043

git-svn-id: http://skia.googlecode.com/svn/trunk@7591 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed