Addresses failures with the following, in some files:
-Wshorten-64-to-32
-Wimplicit-int-conversion
-Wsign-compare
-Wsign-conversion
-Wtautological-unsigned-zero-compare

(This specific CL focuses on .h and win32 .inc files.)

Bug: chromium:1292951
PiperOrigin-RevId: 463835431
Change-Id: If8e5f7f651d5cd96035e23e4623bdb08a7fedabe