mac: Prepare most test code for -Wunused-functions too.

base/debug/trace_event_unittest.cc

Index: base/debug/trace_event_unittest.cc
diff --git a/base/debug/trace_event_unittest.cc b/base/debug/trace_event_unittest.cc
index f94d9ee1869b1a7134ef3ba1bda20ed70d78c2f9..6ad3d667208ffab2a784da380760af5ec7493819 100644
--- a/base/debug/trace_event_unittest.cc
+++ b/base/debug/trace_event_unittest.cc
@@ -841,13 +841,6 @@ void ValidateInstantEventPresentOnEveryThread(const ListValue& trace_parsed,
   }
 }
 
-void TraceCallsWithCachedCategoryPointersPointers(const char* name_str) {
-  TRACE_EVENT0("category name1", name_str);
-  TRACE_EVENT_INSTANT0("category name2", name_str, TRACE_EVENT_SCOPE_THREAD);
-  TRACE_EVENT_BEGIN0("category name3", name_str);
-  TRACE_EVENT_END0("category name4", name_str);
-}
-
 }  // namespace
 
 void HighResSleepForTraceTest(base::TimeDelta elapsed) {