Refactor setup wizard-related code

Extracted setup-related code from WifiSettings, putting it into a new
derived class, WifiSettingsForSetupWizard.

Set taskAffinity to com.android.wizard, for alignment with other
setup wizard-related tasks.

Change-Id: If371f219dac5d3eff8f7899c16cc6f9475be47cf

src/com/android/settings/wifi/WifiSetupActivity.java

@@ -19,6 +19,8 @@ import com.android.settings.ButtonBarHandler;
 
 import android.content.res.Resources;
 
+import java.lang.Class;
+
 public class WifiSetupActivity extends WifiPickerActivity implements ButtonBarHandler {
     // Extra containing the resource name of the theme to be used
     private static final String EXTRA_THEME = "theme";
@@ -41,4 +43,9 @@ public class WifiSetupActivity extends WifiPickerActivity implements ButtonBarHa
         }
         super.onApplyThemeResource(theme, resid, first);
     }
+
+    @Override
+    /* package */ Class getWifiSettingsClass() {
+        return WifiSettingsForSetupWizard.class;
+    }
 }