Fix up all the easy virtual ... SK_OVERRIDE cases.

gm/bitmappremul.cpp

Index: gm/bitmappremul.cpp
diff --git a/gm/bitmappremul.cpp b/gm/bitmappremul.cpp
index e315fafdde4687cdc0c2c3bab7abdb7f17782080..975dd67ae1fcf4938cb6e3b73f366b42d922970c 100644
--- a/gm/bitmappremul.cpp
+++ b/gm/bitmappremul.cpp
@@ -113,11 +113,11 @@ protected:
         return SkString("bitmap_premul");
     }
 
-    virtual SkISize onISize() SK_OVERRIDE {
+    SkISize onISize() SK_OVERRIDE {
         return SkISize::Make(SLIDE_SIZE * 2, SLIDE_SIZE * 2);
     }
 
-    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+    void onDraw(SkCanvas* canvas) SK_OVERRIDE {
         SkScalar slideSize = SkIntToScalar(SLIDE_SIZE);
         canvas->drawBitmap(make_argb8888_gradient(), 0, 0);
         canvas->drawBitmap(make_argb4444_gradient(), slideSize, 0);