Implement isScreenBrightnessBoosted in BridgePowerManager.

Change-Id: I7da132c7522e5c352e14123f059b900008d94c95

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/android/BridgePowerManager.java

@@ -145,4 +145,9 @@ public class BridgePowerManager implements IPowerManager {
     public void boostScreenBrightness(long time) throws RemoteException {
         // pass for now.
     }
+
+    @Override
+    public boolean isScreenBrightnessBoosted() {
+        return false;
+    }
 }