I've heard/lived enough horror stories about AV, outbound-blocking
firewalls, etc. on Windows, that I think the best approach is to have
chrome.exe embed the majority of crashpad_handler and jump to it as
early as possible when running in that mode.
So, move most of crashpad_handler into a static_library with just main()
in the executable target.
R=mark@chromium.org
BUG=chromium:546288, crashpad:27
Review URL: https://codereview.chromium.org/1416873016 .
