When converting from void* to unsigned long long it is dangerous to go
through unsigned long because for VC++ 64-bit builds this will be 32
bits. When casting a pointer to an integral type the safest type to
choose for the integral cast is always intptr_t or uintptr_t.
BUG=440500
NOPRESUBMIT=true
Review URL: https://codereview.webrtc.org/1437433002
Cr-Commit-Position: refs/heads/master@{#10569}