Remove some straggling zoom-related code.

sky/engine/core/animation/css/CSSAnimatableValueFactory.cpp

 /*
  * 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 57 matching lines @@
     case Auto:
     case Intrinsic:
     case MinIntrinsic:
     case MinContent:
     case MaxContent:
     case FillAvailable:
     case FitContent:
         return AnimatableUnknown::create(CSSPrimitiveValue::create(length));
     case MaxSizeNone:
         return AnimatableUnknown::create(CSSValueNone);
-    case ExtendToZoom: // Does not apply to elements.
     case DeviceWidth:
     case DeviceHeight:
         ASSERT_NOT_REACHED();
         return nullptr;
     }
     ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 static PassRefPtr<AnimatableValue> createFromLineHeight(const Length& length, const RenderStyle& style)
@@ skipping 351 matching lines @@
     case CSSPropertyZIndex:
         return createFromDouble(style.zIndex());
     default:
         ASSERT_NOT_REACHED();
         // This return value is to avoid a release crash if possible.
         return AnimatableUnknown::create(nullptr);
     }
 }
 
 } // namespace blink