Update platform classes to use OVERRIDE / FINAL when needed

Source/platform/transforms/IdentityTransformOperation.h

Index: Source/platform/transforms/IdentityTransformOperation.h
diff --git a/Source/platform/transforms/IdentityTransformOperation.h b/Source/platform/transforms/IdentityTransformOperation.h
index 113da29590b154d76c6e588425a82dc2ba29c47e..415b9c83300602f6ad6a964b0277d7954a57b647 100644
--- a/Source/platform/transforms/IdentityTransformOperation.h
+++ b/Source/platform/transforms/IdentityTransformOperation.h
@@ -37,7 +37,7 @@ public:
     }
 
 private:
-    virtual bool isIdentity() const { return true; }
+    virtual bool isIdentity() const OVERRIDE FINAL { return true; }
     virtual OperationType type() const OVERRIDE { return Identity; }
 
     virtual bool operator==(const TransformOperation& o) const
@@ -45,9 +45,9 @@ private:
         return isSameType(o);
     }
 
-    virtual void apply(TransformationMatrix&, const FloatSize&) const { }
+    virtual void apply(TransformationMatrix&, const FloatSize&) const OVERRIDE { }
 
-    virtual PassRefPtr<TransformOperation> blend(const TransformOperation*, double, bool = false)
+    virtual PassRefPtr<TransformOperation> blend(const TransformOperation*, double, bool = false) OVERRIDE
     {
         return this;
     }