Fix getComputedStyle for non-box-layout elements

third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp

 /*
  * Copyright (C) 2004 Zack Rusin <zack@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2011 Sencha, Inc. All rights reserved.
  * Copyright (C) 2015 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ skipping 189 matching lines @@
 
     if (offset.isAuto() && layoutObject) {
         // If the property applies to a positioned element and the resolved value of the display
         // property is not none, the resolved value is the used value.
         if (layoutObject->isInFlowPositioned()) {
             // If e.g. left is auto and right is not auto, then left's computed value is negative right.
             // So we get the opposite length unit and see if it is auto.
             if (opposite.isAuto())
                 return CSSPrimitiveValue::create(0, CSSPrimitiveValue::UnitType::Pixels);
 
-            if (opposite.hasPercent()) {
+            if (opposite.hasPercent() && layoutObject->isBox()) {
                 LayoutUnit containingBlockSize =
                     (propertyID == CSSPropertyLeft || propertyID == CSSPropertyRight) ?
                     toLayoutBox(layoutObject)->containingBlockLogicalWidthForContent() :
                     toLayoutBox(layoutObject)->containingBlockLogicalHeightForGetComputedStyle();
                 return zoomAdjustedPixelValue(-floatValueForLength(opposite, containingBlockSize), style);
             }
-            return zoomAdjustedPixelValue(-opposite.pixels(), style);
+            // Length doesn't provide operator -, so multiply by -1.
+            opposite *= -1.f;

[Timothy Loh, 2016/06/28 00:20:29]

This looks like it might hit an ASSERT if the value is something like calc(1px +
2%)?

[Mr. Kevin, 2016/06/28 00:55:52]

Good catch.  I'll see what I can come up with.

+            return zoomAdjustedPixelValueForLength(opposite, style);
         }
 
-        if (layoutObject->isOutOfFlowPositioned()) {
+        if (layoutObject->isOutOfFlowPositioned() && layoutObject->isBox()) {
             // For fixed and absolute positioned elements, the top, left, bottom, and right
             // are defined relative to the corresponding sides of the containing block.
             LayoutBlock* container = layoutObject->containingBlock();
             const LayoutBox* layoutBox = toLayoutBox(layoutObject);
 
             // clientOffset is the distance from this object's border edge to the container's
             // padding edge. Thus it includes margins which we subtract below.
             const LayoutSize clientOffset =
                 layoutBox->locationOffset() - LayoutSize(container->clientLeft(), container->clientTop());
             LayoutUnit position;
@@ skipping 2768 matching lines @@
     case CSSPropertyAll:
         return nullptr;
     default:
         break;
     }
     ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 } // namespace blink