Update HTML canvas classes to use OVERRIDE / FINAL when needed

Source/core/html/canvas/WebGLDrawBuffers.h

Index: Source/core/html/canvas/WebGLDrawBuffers.h
diff --git a/Source/core/html/canvas/WebGLDrawBuffers.h b/Source/core/html/canvas/WebGLDrawBuffers.h
index 4e3fb56b85ce6ad51aa2526417b03078048b1b00..7b8c0440afd5bb9e054117c920976e2f62f109ee 100644
--- a/Source/core/html/canvas/WebGLDrawBuffers.h
+++ b/Source/core/html/canvas/WebGLDrawBuffers.h
@@ -32,14 +32,14 @@
 
 namespace WebCore {
 
-class WebGLDrawBuffers : public WebGLExtension, public ScriptWrappable {
+class WebGLDrawBuffers FINAL : public WebGLExtension, public ScriptWrappable {
 public:
     static PassRefPtr<WebGLDrawBuffers> create(WebGLRenderingContext*);
     static bool supported(WebGLRenderingContext*);
     static const char* extensionName();
 
     virtual ~WebGLDrawBuffers();
-    virtual ExtensionName name() const;
+    virtual ExtensionName name() const OVERRIDE;
 
     void drawBuffersWEBGL(const Vector<GLenum>& buffers);