Linux: Enable metrics_service_uitest.cc. Take 2.

Linux: Enable metrics_service_uitest.cc.  Take 2.
Relands r18641, original code review: http://codereview.chromium.org/125268
Expect a crash on Windows.
The old method of crashing was flawed on posix (KillProcess just does a SIGTERM).  On Windows though, it would terminate the process with the desired exit code, in order to make DidProcessCrash() return true.  This process termination does not dump crash information though, since it just forcibly terminates the process, like a SIGKILL on posix.  When I switched it to navigate to about:crash though, it actually crashes, and dumps crash information, which the UITest in windows (but not linux/mac) detects.  Therefore, until those platforms can detect, we just use #if defined(OS_WIN) around the expected_crashes = 1.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=18680

[agl, 2009-06-18 00:25:05]

LGTM