Fixes a crash when copying elements with font-weight lighter or bolder

Source/core/editing/EditingStyle.cpp

 /*
  * Copyright (C) 2007, 2008, 2009 Apple Computer, Inc.
  * Copyright (C) 2010, 2011 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1487 matching lines @@
         return false;
 
     // Because b tag can only bold text, there are only two states in plain html: bold and not bold.
     // Collapse all other values to either one of these two states for editing purposes.
     switch (toCSSPrimitiveValue(fontWeight)->getValueID()) {
         case CSSValue100:
         case CSSValue200:
         case CSSValue300:
         case CSSValue400:
         case CSSValue500:
+        case CSSValueLighter:
         case CSSValueNormal:
             return false;
         case CSSValueBold:
+        case CSSValueBolder:

[rniwa-cr, 2013/08/13 20:52:53]

This is incorrect. e.g. in
<span style="font-weight: 100;">hello <span
style="font-weight:bolder">world</span></span>
"world" is not bolded.

To properly fix this bug, we need to do it in its caller and resolve the used
value through the render tree.

         case CSSValue600:
         case CSSValue700:
         case CSSValue800:
         case CSSValue900:
             return true;
         default:
             break;
     }
 
-    ASSERT_NOT_REACHED(); // For CSSValueBolder and CSSValueLighter

[esprehn, 2013/08/13 20:07:43]

Why was this comment here? It seems the author thought this code was unreachable
and those values should never be here.

+    ASSERT_NOT_REACHED();
     return false;
 }
 
 static bool fontWeightIsBold(CSSStyleDeclaration* style)
 {
     ASSERT(style);
     RefPtr<CSSValue> fontWeight = style->getPropertyCSSValueInternal(CSSPropertyFontWeight);
     return fontWeightIsBold(fontWeight.get());
 }
 
@@ skipping 104 matching lines @@
 {
     for (Node* ancestor = node; ancestor; ancestor = ancestor->parentNode()) {
         RefPtr<CSSComputedStyleDeclaration> ancestorStyle = CSSComputedStyleDeclaration::create(ancestor);
         if (!hasTransparentBackgroundColor(ancestorStyle.get()))
             return ancestorStyle->getPropertyCSSValue(CSSPropertyBackgroundColor);
     }
     return 0;
 }
 
 }