Add 'override' specifier to overridden destructor methods

Test: Build
Bug: 37752547
Change-Id: I157e1c2aa5d9d08fcab6055a3ca48c6ed8a050fc
diff --git a/include/gui/ConsumerBase.h b/include/gui/ConsumerBase.h
index 9f8b638..2d77459 100644
--- a/include/gui/ConsumerBase.h
+++ b/include/gui/ConsumerBase.h
@@ -43,7 +43,7 @@
         virtual void onFrameReplaced(const BufferItem& /* item */) {}
     };
 
-    virtual ~ConsumerBase();
+    ~ConsumerBase() override;
 
     // abandon frees all the buffers and puts the ConsumerBase into the
     // 'abandoned' state.  Once put in this state the ConsumerBase can never