Don't log GetScreenBrightnessPercent() errors in VMs

chromeos/dbus/power_manager_client.cc

Index: chromeos/dbus/power_manager_client.cc
diff --git a/chromeos/dbus/power_manager_client.cc b/chromeos/dbus/power_manager_client.cc
index 3c1b484f485496dc086e8192dbcdc06f38938355..c32542525329cfc5a9b08705f462d48b0d4dadb0 100644
--- a/chromeos/dbus/power_manager_client.cc
+++ b/chromeos/dbus/power_manager_client.cc
@@ -29,6 +29,7 @@
 #include "chromeos/dbus/power_manager/policy.pb.h"
 #include "chromeos/dbus/power_manager/power_supply_properties.pb.h"
 #include "chromeos/dbus/power_manager/suspend.pb.h"
+#include "chromeos/system/statistics_provider.h"
 #include "components/device_event_log/device_event_log.h"
 #include "dbus/bus.h"
 #include "dbus/message.h"
@@ -458,8 +459,15 @@ class PowerManagerClientImpl : public PowerManagerClient {
       const GetScreenBrightnessPercentCallback& callback,
       dbus::Response* response) {
     if (!response) {
-      POWER_LOG(ERROR) << "Error calling "
-                       << power_manager::kGetScreenBrightnessPercentMethod;
+      chromeos::system::StatisticsProvider* stats =
+          chromeos::system::StatisticsProvider::GetInstance();
+      std::string hwid;
+      if (stats->GetMachineStatistic(chromeos::system::kHardwareClassKey,
+                                     &hwid) &&
+          hwid != chromeos::system::kHardwareClassValueVM) {

[achuithb, 2016/08/05 21:28:06]

Why not just have a method like IsRunningOnVM() instead?

+        POWER_LOG(ERROR) << "Error calling "
+                         << power_manager::kGetScreenBrightnessPercentMethod;
+      }
       return;
     }
     dbus::MessageReader reader(response);