Update platform classes to use OVERRIDE / FINAL when needed

Source/platform/plugins/PluginListBuilder.h

Index: Source/platform/plugins/PluginListBuilder.h
diff --git a/Source/platform/plugins/PluginListBuilder.h b/Source/platform/plugins/PluginListBuilder.h
index 14aa104dfcffa7978639ce89451f2d897a58bf0f..c803449a39ba2107a9bef572b16deed2fb0eb09a 100644
--- a/Source/platform/plugins/PluginListBuilder.h
+++ b/Source/platform/plugins/PluginListBuilder.h
@@ -37,14 +37,14 @@
 
 namespace WebCore {
 
-class PluginListBuilder : public blink::WebPluginListBuilder {
+class PluginListBuilder FINAL : public blink::WebPluginListBuilder {
 public:
     PluginListBuilder(Vector<WebCore::PluginInfo>* results) : m_results(results) { }
 
     // WebPluginListBuilder methods:
-    virtual void addPlugin(const blink::WebString& name, const blink::WebString& description, const blink::WebString& fileName);
-    virtual void addMediaTypeToLastPlugin(const blink::WebString& name, const blink::WebString& description);
-    virtual void addFileExtensionToLastMediaType(const blink::WebString& extension);
+    virtual void addPlugin(const blink::WebString& name, const blink::WebString& description, const blink::WebString& fileName) OVERRIDE;
+    virtual void addMediaTypeToLastPlugin(const blink::WebString& name, const blink::WebString& description) OVERRIDE;
+    virtual void addFileExtensionToLastMediaType(const blink::WebString& extension) OVERRIDE;
 
 private:
     Vector<PluginInfo>* m_results;