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

src/gpu/gl/mac/SkCreatePlatformGLContext_mac.cpp

Index: src/gpu/gl/mac/SkCreatePlatformGLContext_mac.cpp
diff --git a/src/gpu/gl/mac/SkCreatePlatformGLContext_mac.cpp b/src/gpu/gl/mac/SkCreatePlatformGLContext_mac.cpp
index 5ae1aeb3c7255b26250e23a8e06a3a790c7e55a7..e7f21e0aaee4a31ae2a48c5c2881d69e2d8ff298 100644
--- a/src/gpu/gl/mac/SkCreatePlatformGLContext_mac.cpp
+++ b/src/gpu/gl/mac/SkCreatePlatformGLContext_mac.cpp
@@ -14,9 +14,9 @@ namespace {
 class MacGLContext : public SkGLContext {
 public:
     MacGLContext();
-    virtual ~MacGLContext() SK_OVERRIDE;
-    virtual void makeCurrent() const SK_OVERRIDE;
-    virtual void swapBuffers() const SK_OVERRIDE;
+    ~MacGLContext() SK_OVERRIDE;
+    void makeCurrent() const SK_OVERRIDE;
+    void swapBuffers() const SK_OVERRIDE;
 
 private:
     void destroyGLContext();