Declare Visualizer::setEnabled() 'final'

We call the virtual method setEnabled() from Visualizer's
destructor.  In the destructor, the virtual binding is not used.
This isn't a problem for any current code, but to future-proof
against a possible future subclass of Visualizer, we declare
this method 'final'.

Test: TreeHugger
Change-Id: I703580b37cc1bf7f411caa723f95a691dff840a5

media/jni/audioeffect/Visualizer.h

@@ -73,7 +73,8 @@ public:
 
                         ~Visualizer();
 
-    virtual status_t    setEnabled(bool enabled);
+    // Declared 'final' because we call this in ~Visualizer().
+    status_t    setEnabled(bool enabled) final;
 
     // maximum capture size in samples
     static uint32_t getMaxCaptureSize() { return VISUALIZER_CAPTURE_SIZE_MAX; }