Add the 'lighter' composite operation to feComposite.

Source/platform/graphics/filters/FEComposite.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 18 matching lines @@
 
 namespace blink {
 
 enum CompositeOperationType {
     FECOMPOSITE_OPERATOR_UNKNOWN    = 0,
     FECOMPOSITE_OPERATOR_OVER       = 1,
     FECOMPOSITE_OPERATOR_IN         = 2,
     FECOMPOSITE_OPERATOR_OUT        = 3,
     FECOMPOSITE_OPERATOR_ATOP       = 4,
     FECOMPOSITE_OPERATOR_XOR        = 5,
-    FECOMPOSITE_OPERATOR_ARITHMETIC = 6
+    FECOMPOSITE_OPERATOR_ARITHMETIC = 6,
+    FECOMPOSITE_OPERATOR_LIGHTER    = 7
 };
 
 class PLATFORM_EXPORT FEComposite : public FilterEffect {
 public:
     static PassRefPtrWillBeRawPtr<FEComposite> create(Filter*, const CompositeOperationType&, float, float, float, float);
 
     CompositeOperationType operation() const;
     bool setOperation(CompositeOperationType);
 
     float k1() const;
@@ skipping 32 matching lines @@
     CompositeOperationType m_type;
     float m_k1;
     float m_k2;
     float m_k3;
     float m_k4;
 };
 
 } // namespace blink
 
 #endif // FEComposite_h