Add full SetThreadPriority support to Windows.

base/threading/platform_thread_freebsd.cc

Index: base/threading/platform_thread_freebsd.cc
diff --git a/base/threading/platform_thread_freebsd.cc b/base/threading/platform_thread_freebsd.cc
index a163f650443d08f1602ff295e8c985dab7c7ddd2..6de2e2b3a3ec02f2b53d9441c1b156813955be32 100644
--- a/base/threading/platform_thread_freebsd.cc
+++ b/base/threading/platform_thread_freebsd.cc
@@ -46,6 +46,23 @@ bool HandleSetThreadPriorityForPlatform(PlatformThreadHandle handle,
 #endif
 }
 
+bool HandleGetThreadPriorityForPlatform(PlatformThreadHandle handle,
+                                        ThreadPriority* priority) {
+#if !defined(OS_NACL)
+  // Mirrors HandleSetThreadPriorityForPlatform()'s implementation.

[rvargas (doing something else), 2015/03/19 22:19:21]

Do we need this comment?

[gab, 2015/03/30 20:14:45]

I like it, if anything it answers your question below :-)

[rvargas (doing something else), 2015/03/30 22:31:22]

It doesn't answer my question :p. I noticed you were following the other
function, and both seem buggy... but this comment seems too general for my taste
(we have tons of methods that are a logical complement to others so we could add
the same comment everywhere).

If what you want to point out is that the bug is not really yours, then the
comment is way too subtle.

Up to you.

+  int maybe_sched_rr = 0;
+  struct sched_param maybe_realtime_prio = {0};
+  if (pthread_getschedparam(pthread_self(), &maybe_sched_rr,

[rvargas (doing something else), 2015/03/19 22:19:21]

why self() and not handle?

[gab, 2015/03/30 20:14:45]

Because it mirrors HandleSetThreadPriorityForPlatform()'s implementation.

I agree that this looks broken (or at least doesn't respect the existing API --
filed http://crbug.com/468793 for someoen to investigate POSIX thread priority
once this lands)

[rvargas (doing something else), 2015/03/30 22:31:22]

I don't think that's a strong enough justification (unless of course the code is
correct). We should clarify this behavior before checking in more code, or at
least add a clear TODO pointing to the bug you filed.

[gab, 2015/03/31 14:02:33]

Added a TODO, will find an owner once this lands.

+                            &maybe_realtime_prio) == 0 &&
+      maybe_sched_rr == SCHED_RR &&
+      maybe_realtime_prio.sched_priority == kRealTimePrio.sched_priority) {
+    *priority = kThreadPriority_RealtimeAudio;
+    return true;
+  }
+#endif
+  return false;
+}
+
 }  // namespace internal
 
 // static