Remove support for -webkit-line-clamp

Source/core/css/CSSParser-in.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 2564 matching lines @@
         else
             validPrimitive = validUnit(value, FNumber | FNonNeg) && value->fValue == 1;
         break;
     case CSSPropertyWebkitColumnWidth:         // auto | <length>
         parsedValue = parseColumnWidth();
         break;
     // End of CSS3 properties
 
     // Apple specific properties.  These will never be standardized and are purely to
     // support custom WebKit-based Apple applications.
-    case CSSPropertyWebkitLineClamp:
-        // When specifying number of lines, don't allow 0 as a valid value
-        // When specifying either type of unit, require non-negative integers
-        validPrimitive = (!id && (value->unit == CSSPrimitiveValue::CSS_PERCENTAGE || value->fValue) && validUnit(value, FInteger | FPercent | FNonNeg, CSSQuirksMode));
-        break;
-
     case CSSPropertyWebkitFontSizeDelta:           // <length>
         validPrimitive = validUnit(value, FLength);
         break;
 
     case CSSPropertyWebkitHighlight:
         if (id == CSSValueNone || value->unit == CSSPrimitiveValue::CSS_STRING)
             validPrimitive = true;
         break;
 
     case CSSPropertyWebkitHyphenateCharacter:
@@ skipping 9428 matching lines @@
 {
     // The tokenizer checks for the construct of an+b.
     // However, since the {ident} rule precedes the {nth} rule, some of those
     // tokens are identified as string literal. Furthermore we need to accept
     // "odd" and "even" which does not match to an+b.
     return equalIgnoringCase(token, "odd") || equalIgnoringCase(token, "even")
         || equalIgnoringCase(token, "n") || equalIgnoringCase(token, "-n");
 }
 
 }