From c843e5b33ae305c06c98a6832b2de669fc1ef39c Mon Sep 17 00:00:00 2001
From: "L. David Baron" <dbaron@dbaron.org>
Date: Sat, 3 Jul 2010 12:25:37 -0700
Subject: [PATCH] Make nsStyleAnimation::ComputeDistance not crash when given
 -moz-transform: none.  (Bug 576761)  (pending review)

--HG--
extra : transplant_source : _hY%B1%23%2Cb%D2%19R%BB%24%A4%9C%1B%16R%5C%8Ee
---
 layout/style/nsStyleAnimation.cpp | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/layout/style/nsStyleAnimation.cpp b/layout/style/nsStyleAnimation.cpp
index ef9bec08ffa8..c1d71d114910 100644
--- a/layout/style/nsStyleAnimation.cpp
+++ b/layout/style/nsStyleAnimation.cpp
@@ -408,11 +408,18 @@ nsStyleAnimation::ComputeDistance(nsCSSProperty aProperty,
       const nsCSSValueList *list1 = aStartValue.GetCSSValueListValue();
       const nsCSSValueList *list2 = aEndValue.GetCSSValueListValue();
 
+      nsStyleTransformMatrix matrix1, matrix2; // initialized to identity
+
       PRBool dummy;
-      nsStyleTransformMatrix matrix1 =
-        nsStyleTransformMatrix::ReadTransforms(list1, nsnull, nsnull, dummy),
-                             matrix2 =
-        nsStyleTransformMatrix::ReadTransforms(list2, nsnull, nsnull, dummy);
+      if (list1->mValue.GetUnit() != eCSSUnit_None) {
+        matrix1 = nsStyleTransformMatrix::ReadTransforms(list1, nsnull,
+                                                         nsnull, dummy);
+      }
+      if (list2->mValue.GetUnit() != eCSSUnit_None) {
+        matrix2 = nsStyleTransformMatrix::ReadTransforms(list2, nsnull,
+                                                         nsnull, dummy);
+      }
+
       double diff;
       double squareDistance = 0.0;
       for (PRUint32 i = 0; i < 4; ++i) {