Bug 337854 crash [@ nsTreeContentView::GetCell].

Patch by alfred.peng@sun.com.
neil: review+
roc: superreview+

content/xul/templates/src/nsXULTreeBuilder.cpp

@@ -1463,9 +1463,9 @@ nsXULTreeBuilder::GetTemplateActionCellFor(PRInt32 aRow,
     nsCOMPtr<nsIContent> row;
     GetTemplateActionRowFor(aRow, getter_AddRefs(row));
     if (row) {
-        const PRUnichar* colID;
+        nsCOMPtr<nsIAtom> colAtom;
         PRInt32 colIndex;
-        aCol->GetIdConst(&colID);
+        aCol->GetAtom(getter_AddRefs(colAtom));
         aCol->GetIndex(&colIndex);
 
         PRUint32 count = row->GetChildCount();
@@ -1475,10 +1475,9 @@ nsXULTreeBuilder::GetTemplateActionCellFor(PRInt32 aRow,
 
             if (child->NodeInfo()->Equals(nsXULAtoms::treecell,
                                           kNameSpaceID_XUL)) {
-                if (colID[0] != 0 &&
+                if (colAtom &&
                     child->AttrValueIs(kNameSpaceID_None, nsXULAtoms::ref,
-                                       nsDependentString(colID),
-                                       eCaseMatters)) {
+                                       colAtom, eCaseMatters)) {
                     *aResult = child;
                     break;
                 }

layout/xul/base/src/tree/src/nsTreeContentView.cpp

@@ -1449,9 +1449,9 @@ nsTreeContentView::UpdateParentIndexes(PRInt32 aIndex, PRInt32 aSkip, PRInt32 aC
 nsIContent*
 nsTreeContentView::GetCell(nsIContent* aContainer, nsITreeColumn* aCol)
 {
-  const PRUnichar* colID;
+  nsCOMPtr<nsIAtom> colAtom;
   PRInt32 colIndex;
-  aCol->GetIdConst(&colID);
+  aCol->GetAtom(getter_AddRefs(colAtom));
   aCol->GetIndex(&colIndex);
 
   // Traverse through cells, try to find the cell by "ref" attribute or by cell
@@ -1463,9 +1463,8 @@ nsTreeContentView::GetCell(nsIContent* aContainer, nsITreeColumn* aCol)
     nsCOMPtr<nsIContent> cell = *iter;
 
     if (cell->Tag() == nsXULAtoms::treecell) {
-      if (colID[0] != 0 && cell->AttrValueIs(kNameSpaceID_None, nsXULAtoms::ref,
-                                             nsDependentString(colID),
-                                             eCaseMatters)) {
+      if (colAtom && cell->AttrValueIs(kNameSpaceID_None, nsXULAtoms::ref,
+                                       colAtom, eCaseMatters)) {
         result = cell;
         break;
       }