fix reference counting for GtkWidgets created from java

GtkWidgets extend GInitiallyUnowned and are automatically freed when
removing from parent widget. We need to add an extra reference, to make
sure the object keeps alive as long as the java widget has a reference
to it

src/api-impl/android/view/View.java

@@ -775,7 +775,9 @@ public class View extends Object {
 
 	public static HashMap<Integer, View> view_by_id = new HashMap<Integer, View>();
 
-	public View() {} // FIXME
+	public View() {
+		this(Context.this_application);
+	} // FIXME
 
 	public View(Context context, AttributeSet attrs) {
 		this(context, attrs, 0);
@@ -843,6 +845,7 @@ public class View extends Object {
 
 	protected native long native_constructor(Context context, AttributeSet attrs); // will create a custom GtkWidget with a custom drawing function
 	private native void native_set_size_request(int width, int height);
+	protected native void native_destructor(long widget);
 
 	// --- stubs
 
@@ -1052,4 +1055,13 @@ public class View extends Object {
 	public int getVisibility() {return View.VISIBLE;}
 
 	public boolean isInEditMode() {return false;}
+
+	@Override
+	protected void finalize() throws Throwable {
+		try {
+			native_destructor(widget);
+		} finally {
+			super.finalize();
+		}
+	}
 }