Less magic numbers in converting CSS lengths of cm/mm/pc/pt types.

Source/core/css/CSSPrimitiveValue.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2012 Apple 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 570 matching lines @@
             else
                 factor = 1.0;
             break;
         case CSS_CHS:
             factor = style->fontMetrics().zeroWidth();
             break;
         case CSS_PX:
             factor = 1.0;
             break;
         case CSS_CM:
-            factor = cssPixelsPerInch / 2.54; // (2.54 cm/in)
+            factor = cssPixelsPerCentimeter;
             break;
         case CSS_MM:
-            factor = cssPixelsPerInch / 25.4;
+            factor = cssPixelsPerMillimeter;
             break;
         case CSS_IN:
             factor = cssPixelsPerInch;
             break;
         case CSS_PT:
-            factor = cssPixelsPerInch / 72.0;
+            factor = cssPixelsPerPoint;
             break;
         case CSS_PC:
-            // 1 pc == 12 pt
-            factor = cssPixelsPerInch * 12.0 / 72.0;
+            factor = cssPixelsPerPica;
             break;
         case CSS_CALC_PERCENTAGE_WITH_LENGTH:
         case CSS_CALC_PERCENTAGE_WITH_NUMBER:
             ASSERT_NOT_REACHED();
             return -1.0;
         default:
             ASSERT_NOT_REACHED();
             return -1.0;
     }
 
@@ skipping 20 matching lines @@
     double factor = 1.0;
     // FIXME: the switch can be replaced by an array of scale factors.
     switch (unitType) {
     // These are "canonical" units in their respective categories.
     case CSS_PX:
     case CSS_DEG:
     case CSS_MS:
     case CSS_HZ:
         break;
     case CSS_CM:
-        factor = cssPixelsPerInch / 2.54; // (2.54 cm/in)
+        factor = cssPixelsPerCentimeter;
         break;
     case CSS_DPCM:
-        factor = 2.54 / cssPixelsPerInch; // (2.54 cm/in)
+        factor = 1 / cssPixelsPerCentimeter;
         break;
     case CSS_MM:
-        factor = cssPixelsPerInch / 25.4;
+        factor = cssPixelsPerMillimeter;
         break;
     case CSS_IN:
         factor = cssPixelsPerInch;
         break;
     case CSS_DPI:
         factor = 1 / cssPixelsPerInch;
         break;
     case CSS_PT:
-        factor = cssPixelsPerInch / 72.0;
+        factor = cssPixelsPerPoint;
         break;
     case CSS_PC:
-        factor = cssPixelsPerInch * 12.0 / 72.0; // 1 pc == 12 pt
+        factor = cssPixelsPerPica;
         break;
     case CSS_RAD:
         factor = 180 / piDouble;
         break;
     case CSS_GRAD:
         factor = 0.9;
         break;
     case CSS_TURN:
         factor = 360;
         break;
@@ skipping 657 matching lines @@
         return m_value.parserOperator == other.m_value.parserOperator;
     case CSS_CALC:
         return m_value.calc && other.m_value.calc && m_value.calc->equals(*other.m_value.calc);
     case CSS_SHAPE:
         return m_value.shape && other.m_value.shape && m_value.shape->equals(*other.m_value.shape);
     }
     return false;
 }
 
 } // namespace WebCore