Turn ThreadPriority enum into an enum class.

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 dc5d34b2c51168f3c0d639920074e61689e79a33..7ba4eedccbaf540168e0fe45875b991718e06e49 100644
--- a/base/threading/platform_thread_freebsd.cc
+++ b/base/threading/platform_thread_freebsd.cc
@@ -30,10 +30,10 @@ const struct sched_param kRealTimePrio = {8};
 }  // namespace
 
 const ThreadPriorityToNiceValuePair kThreadPriorityToNiceValueMap[4] = {
-  { kThreadPriority_RealtimeAudio, -10 },
-  { kThreadPriority_Background, 10 },
-  { kThreadPriority_Normal, 0 },
-  { kThreadPriority_Display, -6 },
+    {ThreadPriority::BACKGROUND, 10},
+    {ThreadPriority::NORMAL, 0},
+    {ThreadPriority::DISPLAY, -6},
+    {ThreadPriority::REALTIME_AUDIO, -10},
 }
 
 bool SetThreadPriorityForPlatform(PlatformThreadHandle handle,
@@ -41,7 +41,7 @@ bool SetThreadPriorityForPlatform(PlatformThreadHandle handle,
 #if !defined(OS_NACL)
   // TODO(gab): Assess the correctness of using |pthread_self()| below instead
   // of |handle|. http://crbug.com/468793.
-  return priority == kThreadPriority_RealtimeAudio &&
+  return priority == ThreadPriority::REALTIME_AUDIO &&
          pthread_setschedparam(pthread_self(), SCHED_RR, &kRealTimePrio) == 0;
 #else
   return false;
@@ -59,7 +59,7 @@ bool GetThreadPriorityForPlatform(PlatformThreadHandle handle,
                             &maybe_realtime_prio) == 0 &&
       maybe_sched_rr == SCHED_RR &&
       maybe_realtime_prio.sched_priority == kRealTimePrio.sched_priority) {
-    *priority = kThreadPriority_RealtimeAudio;
+    *priority = ThreadPriority::REALTIME_AUDIO;
     return true;
   }
 #endif