Don't log GetScreenBrightnessPercent() errors in VMs

chromeos/dbus/power_manager_client.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chromeos/dbus/power_manager_client.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <memory>
@@ skipping 11 matching lines @@
 #include "base/strings/stringprintf.h"
 #include "base/threading/platform_thread.h"
 #include "base/timer/timer.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/fake_power_manager_client.h"
 #include "chromeos/dbus/power_manager/input_event.pb.h"
 #include "chromeos/dbus/power_manager/peripheral_battery_status.pb.h"
 #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"
 #include "dbus/object_path.h"
 #include "dbus/object_proxy.h"
 
 namespace chromeos {
 
 // Maximum amount of time that the power manager will wait for Chrome to
 // say that it's ready for the system to be suspended, in milliseconds.
@@ skipping 409 matching lines @@
       POWER_LOG(ERROR) << "Unable to decode "
                        << power_manager::kGetPowerSupplyPropertiesMethod
                        << " response";
     }
   }
 
   void OnGetScreenBrightnessPercent(
       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);
     double percent = 0.0;
     if (!reader.PopDouble(&percent))
       POWER_LOG(ERROR) << "Error reading response from powerd: "
                        << response->ToString();
     callback.Run(percent);
   }
 
@@ skipping 327 matching lines @@
 // static
 PowerManagerClient* PowerManagerClient::Create(
     DBusClientImplementationType type) {
   if (type == REAL_DBUS_CLIENT_IMPLEMENTATION)
     return new PowerManagerClientImpl();
   DCHECK_EQ(STUB_DBUS_CLIENT_IMPLEMENTATION, type);
   return new FakePowerManagerClient();
 }
 
 }  // namespace chromeos