Added merge method to OperaOptions

Signed-off-by: Alexei Barantsev <barancev@gmail.com>

Author: ham1

java/client/src/org/openqa/selenium/opera/OperaOptions.java

@@ -27,6 +27,7 @@
 import com.google.common.collect.Maps;
 import com.google.common.io.Files;
 
+import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.MutableCapabilities;
 import org.openqa.selenium.Proxy;
 import org.openqa.selenium.WebDriverException;
@@ -76,6 +77,12 @@ public OperaOptions() {
     setCapability(BROWSER_NAME, OPERA_BLINK);
   }
 
+  @Override
+  public OperaOptions merge(Capabilities extraCapabilities) {
+    super.merge(extraCapabilities);
+    return this;
+  }
+
   /**
    * Sets the path to the Opera executable. This path should exist on the
    * machine which will launch Opera. The path should either be absolute or