Fix incorrect percentage top for positioned elements.

Source/core/layout/LayoutBox.cpp

Index: Source/core/layout/LayoutBox.cpp
diff --git a/Source/core/layout/LayoutBox.cpp b/Source/core/layout/LayoutBox.cpp
index a24c390b55c02b4bb0875bc2132b7c71861930ea..4a01ca9f14d6ad0093bb4b41921200820118549e 100644
--- a/Source/core/layout/LayoutBox.cpp
+++ b/Source/core/layout/LayoutBox.cpp
@@ -1521,6 +1521,24 @@ LayoutUnit LayoutBox::shrinkLogicalWidthToAvoidFloats(LayoutUnit childMarginStar
     return width;
 }
 
+LayoutUnit LayoutBox::containingBlockLogicalHeightForComputedStyle() const
+{
+    if (hasOverrideContainingBlockLogicalHeight())
+        return overrideContainingBlockContentLogicalHeight();
+
+    LayoutUnit height;
+    if (isPositioned()) {
+        LayoutBoxModelObject* cb = toLayoutBoxModelObject(container());
+        height = containingBlockLogicalHeightForPositioned(cb);
+        if (styleRef().position() != AbsolutePosition)
+            height -= cb->paddingLogicalHeight();
+    } else {
+        height = containingBlockLogicalHeightForContent(ExcludeMarginBorderPadding);

[mstensho (USE GERRIT), 2015/04/13 21:40:04]

Blink coding style prefers early returns. You could do this:

if (!isPositioned())
    return containingBlockLogicalHeightForContent(ExcludeMarginBorderPadding);
LayoutUnit height;
LayoutBoxModelObject* cb = toLayoutBoxModelObject(container());
...

[changseok, 2015/04/14 06:27:21]

Done.

+    }
+
+    return height;
+}
+
 LayoutUnit LayoutBox::containingBlockLogicalWidthForContent() const
 {
     if (hasOverrideContainingBlockLogicalWidth())