chromeos: Add support for dimming the screen.

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 26f67055d9dbabe2189c448c9ab4ce504d8d2de3..ca50df7794a0ddb1d5bd9c3beb8077a1a4915021 100644
--- a/chromeos/dbus/power_manager_client.cc
+++ b/chromeos/dbus/power_manager_client.cc
@@ -111,6 +111,15 @@ class PowerManagerClientImpl : public PowerManagerClient {
                    weak_ptr_factory_.GetWeakPtr()),
         base::Bind(&PowerManagerClientImpl::SignalConnected,
                    weak_ptr_factory_.GetWeakPtr()));
+
+    power_manager_proxy_->ConnectToSignal(
+        power_manager::kPowerManagerInterface,
+        power_manager::kSoftwareScreenDimmingRequestedSignal,
+        base::Bind(
+            &PowerManagerClientImpl::SoftwareScreenDimmingRequestedReceived,
+            weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&PowerManagerClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
   }
 
   virtual ~PowerManagerClientImpl() {
@@ -435,7 +444,6 @@ class PowerManagerClientImpl : public PowerManagerClient {
     FOR_EACH_OBSERVER(Observer, observers_, UnlockScreenFailed());
   }
 
-
   void IdleNotifySignalReceived(dbus::Signal* signal) {
     dbus::MessageReader reader(signal);
     int64 threshold = 0;
@@ -464,6 +472,28 @@ class PowerManagerClientImpl : public PowerManagerClient {
     FOR_EACH_OBSERVER(Observer, observers_, ActiveNotify());
   }
 
+  void SoftwareScreenDimmingRequestedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    int32 signal_state = 0;
+    if (!reader.PopInt32(&signal_state)) {
+      LOG(ERROR) << "Screen dimming signal had incorrect parameters: "
+                 << signal->ToString();
+      return;
+    }
+
+    Observer::ScreenDimmingState state = Observer::SCREEN_DIMMING_NONE;
+    switch (signal_state) {
+      case power_manager::kSoftwareScreenDimmingNone:
+        state = Observer::SCREEN_DIMMING_NONE;
+        break;
+      case power_manager::kSoftwareScreenDimmingIdle:
+        state = Observer::SCREEN_DIMMING_IDLE;
+        break;
+      default:
+        LOG(ERROR) << "Unhandled screen dimming state " << signal_state;
+    }
+    FOR_EACH_OBSERVER(Observer, observers_, ScreenDimmingRequested(state));
+  }
 
   dbus::ObjectProxy* power_manager_proxy_;
   dbus::ObjectProxy* session_manager_proxy_;