Update platform classes to use OVERRIDE / FINAL when needed

Source/platform/transforms/Matrix3DTransformOperation.h

Index: Source/platform/transforms/Matrix3DTransformOperation.h
diff --git a/Source/platform/transforms/Matrix3DTransformOperation.h b/Source/platform/transforms/Matrix3DTransformOperation.h
index 9f6711d92e77b947bf3055b631169fc5c3b7f903..b2f575b8145060bbef6cc63c2a5b6b972b841dee 100644
--- a/Source/platform/transforms/Matrix3DTransformOperation.h
+++ b/Source/platform/transforms/Matrix3DTransformOperation.h
@@ -40,7 +40,7 @@ public:
     TransformationMatrix matrix() const {return m_matrix; }
 
 private:
-    virtual bool isIdentity() const { return m_matrix.isIdentity(); }
+    virtual bool isIdentity() const OVERRIDE { return m_matrix.isIdentity(); }
 
     virtual OperationType type() const OVERRIDE { return Matrix3D; }
 
@@ -52,12 +52,12 @@ private:
         return m_matrix == m->m_matrix;
     }
 
-    virtual void apply(TransformationMatrix& transform, const FloatSize&) const
+    virtual void apply(TransformationMatrix& transform, const FloatSize&) const OVERRIDE
     {
         transform.multiply(TransformationMatrix(m_matrix));
     }
 
-    virtual PassRefPtr<TransformOperation> blend(const TransformOperation* from, double progress, bool blendToIdentity = false);
+    virtual PassRefPtr<TransformOperation> blend(const TransformOperation* from, double progress, bool blendToIdentity = false) OVERRIDE;
 
     Matrix3DTransformOperation(const TransformationMatrix& mat)
     {