(This is a merge of http://go/wvgerrit/134311.)
This patch widens the variable type used for lengths in wvcrc32 from
int to size_t. This fixes code that would trigger -Wshorten-64-to-32 by
implicitly narrowing a variable from 64 to 32 bits.
Bug: 194971260
Test: x86-64
Change-Id: I2887c18ff2a2c6dd3d65f966d9d1203fb050f736