Fix black background when locking with fullscreen window:

base/time_mac.cc

Index: base/time_mac.cc
diff --git a/base/time_mac.cc b/base/time_mac.cc
index ca10bc88662cc1c470bf34e68bca0634899f5e5c..8d00265340ae57e87b93280a8c090c3128a038a6 100644
--- a/base/time_mac.cc
+++ b/base/time_mac.cc
@@ -47,6 +47,8 @@ const int64 Time::kTimeTToMicrosecondsOffset = kWindowsEpochDeltaMicroseconds;
 
 // static
 Time Time::Now() {
+  if (TimeFactory::instance())
+    return TimeFactory::instance()->TimeNow();
   return FromCFAbsoluteTime(CFAbsoluteTimeGetCurrent());
 }
 
@@ -131,6 +133,9 @@ void Time::Explode(bool is_local, Exploded* exploded) const {
 
 // static
 TimeTicks TimeTicks::Now() {
+  if (TimeFactory::instance())
+    return TimeFactory::instance()->TimeTicksNow();
+
   uint64_t absolute_micro;
 
   static mach_timebase_info_data_t timebase_info;