Replace FOR_EACH_OBSERVER in chromeos/ with range-based for

chromeos/dbus/system_clock_client.cc

Index: chromeos/dbus/system_clock_client.cc
diff --git a/chromeos/dbus/system_clock_client.cc b/chromeos/dbus/system_clock_client.cc
index 600536d54953b6b79207ef73f2a53c9c21048211..fe27f58e67a9084307f01ed0b563bceb64c81b75 100644
--- a/chromeos/dbus/system_clock_client.cc
+++ b/chromeos/dbus/system_clock_client.cc
@@ -84,7 +84,8 @@ class SystemClockClientImpl : public SystemClockClient {
   void TimeUpdatedReceived(dbus::Signal* signal) {
     VLOG(1) << "TimeUpdated signal received: " << signal->ToString();
     dbus::MessageReader reader(signal);
-    FOR_EACH_OBSERVER(Observer, observers_, SystemClockUpdated());
+    for (auto& observer : observers_)
+      observer.SystemClockUpdated();
 
     // Check if the system clock can be changed now.
     GetCanSet();
@@ -119,8 +120,8 @@ class SystemClockClientImpl : public SystemClockClient {
     can_set_time_initialized_ = true;
     can_set_time_ = can_set_time;
 
-    FOR_EACH_OBSERVER(
-        Observer, observers_, SystemClockCanSetTimeChanged(can_set_time));
+    for (auto& observer : observers_)
+      observer.SystemClockCanSetTimeChanged(can_set_time);
   }
 
   // Check whether the time can be set.