[CSS Blending] Implement mix-blend-mode in software.

public/platform/WebCompositingReasons.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 31 matching lines @@
 const uint64_t CompositingReasonVideo                                  = static_cast<uint64_t>(1) << 1;
 const uint64_t CompositingReasonCanvas                                 = static_cast<uint64_t>(1) << 2;
 const uint64_t CompositingReasonPlugin                                 = static_cast<uint64_t>(1) << 3;
 const uint64_t CompositingReasonIFrame                                 = static_cast<uint64_t>(1) << 4;
 const uint64_t CompositingReasonBackfaceVisibilityHidden               = static_cast<uint64_t>(1) << 5;
 const uint64_t CompositingReasonAnimation                              = static_cast<uint64_t>(1) << 6;
 const uint64_t CompositingReasonFilters                                = static_cast<uint64_t>(1) << 7;
 const uint64_t CompositingReasonPositionFixed                          = static_cast<uint64_t>(1) << 8;
 const uint64_t CompositingReasonPositionSticky                         = static_cast<uint64_t>(1) << 9;
 const uint64_t CompositingReasonOverflowScrollingTouch                 = static_cast<uint64_t>(1) << 10;
-const uint64_t CompositingReasonBlending                               = static_cast<uint64_t>(1) << 11;
 const uint64_t CompositingReasonAssumedOverlap                         = static_cast<uint64_t>(1) << 12;
 const uint64_t CompositingReasonOverlap                                = static_cast<uint64_t>(1) << 13;
 const uint64_t CompositingReasonNegativeZIndexChildren                 = static_cast<uint64_t>(1) << 14;
 const uint64_t CompositingReasonTransformWithCompositedDescendants     = static_cast<uint64_t>(1) << 15;
 const uint64_t CompositingReasonOpacityWithCompositedDescendants       = static_cast<uint64_t>(1) << 16;
 const uint64_t CompositingReasonMaskWithCompositedDescendants          = static_cast<uint64_t>(1) << 17;
 const uint64_t CompositingReasonReflectionWithCompositedDescendants    = static_cast<uint64_t>(1) << 18;
 const uint64_t CompositingReasonFilterWithCompositedDescendants        = static_cast<uint64_t>(1) << 19;
 const uint64_t CompositingReasonBlendingWithCompositedDescendants      = static_cast<uint64_t>(1) << 20;
 const uint64_t CompositingReasonClipsCompositingDescendants            = static_cast<uint64_t>(1) << 21;
 const uint64_t CompositingReasonPerspective                            = static_cast<uint64_t>(1) << 22;
 const uint64_t CompositingReasonPreserve3D                             = static_cast<uint64_t>(1) << 23;
 const uint64_t CompositingReasonReflectionOfCompositedParent           = static_cast<uint64_t>(1) << 24;
 const uint64_t CompositingReasonRoot                                   = static_cast<uint64_t>(1) << 25;
 const uint64_t CompositingReasonLayerForClip                           = static_cast<uint64_t>(1) << 26;
 const uint64_t CompositingReasonLayerForScrollbar                      = static_cast<uint64_t>(1) << 27;
 const uint64_t CompositingReasonLayerForScrollingContainer             = static_cast<uint64_t>(1) << 28;
 const uint64_t CompositingReasonLayerForForeground                     = static_cast<uint64_t>(1) << 29;
 const uint64_t CompositingReasonLayerForBackground                     = static_cast<uint64_t>(1) << 30;
 const uint64_t CompositingReasonLayerForMask                           = static_cast<uint64_t>(1) << 31;
 const uint64_t CompositingReasonOverflowScrollingParent                = static_cast<uint64_t>(1) << 32;
 const uint64_t CompositingReasonOutOfFlowClipping                      = static_cast<uint64_t>(1) << 33;
 
 typedef uint64_t WebCompositingReasons;
 
 } // namespace WebKit
 
 #endif // WebCompositingReasons_h