Android: List extra packages as well

These packages should get listed as well as they contain
(at least on Windows) essential packages.

Change-Id: Ia8fb8fc641ac6d9a7fba8f65a31ef65eae560a99
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/android/androidsdkpackage.cpp

@@ -269,4 +269,19 @@ AndroidSdkPackage::PackageType EmulatorTools::type() const
     return AndroidSdkPackage::EmulatorToolsPackage;
 }
 
+ExtraTools::ExtraTools(QVersionNumber revision, QString sdkStylePathStr, QObject *parent) :
+    AndroidSdkPackage(revision, sdkStylePathStr, parent)
+{
+}
+
+bool ExtraTools::isValid() const
+{
+    return installedLocation().exists();
+}
+
+AndroidSdkPackage::PackageType ExtraTools::type() const
+{
+    return AndroidSdkPackage::ExtraToolsPackage;
+}
+
 } // namespace Android