Bug 1272983 part 3: Use more forgiving padding getter in nsTreeBodyFrame.cpp, for better behavior with percent padding. r=dbaron

MozReview-Commit-ID: 10wFgGQ2Dqt

layout/reftests/xul/reftest.list

@@ -72,3 +72,5 @@ skip-if((B2G&&browserIsRemote)||Mulet) == object-position-png-002.xul object-pos
 # annotation with "skip-if((B2G&&browserIsRemote)||Mulet)", like above tests.
 skip == treecell-image-svg-1a.xul treecell-image-svg-1-ref.xul # bug 1218954
 skip == treecell-image-svg-1b.xul treecell-image-svg-1-ref.xul # bug 1218954
+
+skip-if((B2G&&browserIsRemote)||Mulet) == treechildren-padding-percent-1.xul treechildren-padding-percent-1-ref.xul

layout/reftests/xul/treechildren-padding-percent-1-ref.xul

@@ -0,0 +1,19 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <style>
+  </style>
+  <tree seltype="single" flex="1">
+    <treecols>
+      <treecol flex="1"/>
+    </treecols>
+    <treechildren>
+      <treeitem>
+        <treerow>
+          <treecell label="I am a treecell"></treecell>
+        </treerow>
+      </treeitem>
+    </treechildren>
+  </tree>
+</window>

layout/reftests/xul/treechildren-padding-percent-1.xul

@@ -0,0 +1,19 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <style>
+  </style>
+  <tree seltype="single" flex="1">
+    <treecols>
+      <treecol flex="1"/>
+    </treecols>
+    <treechildren style="padding: 5%">
+      <treeitem>
+        <treerow>
+          <treecell label="I am a treecell"></treecell>
+        </treerow>
+      </treeitem>
+    </treechildren>
+  </tree>
+</window>

layout/xul/tree/nsTreeBodyFrame.cpp

@@ -150,7 +150,7 @@ static void
 GetBorderPadding(nsStyleContext* aContext, nsMargin& aMargin)
 {
   aMargin.SizeTo(0, 0, 0, 0);
-  aContext->StylePadding()->GetPaddingNoPercentage(aMargin);
+  aContext->StylePadding()->GetPadding(aMargin);
   aMargin += aContext->StyleBorder()->GetComputedBorder();
 }