Make SkTInternalLList::validate validate all nodes

include/core/SkTInternalLList.h

Index: include/core/SkTInternalLList.h
diff --git a/include/core/SkTInternalLList.h b/include/core/SkTInternalLList.h
index a6b6f153530796097c1f92a7294220f2209bd481..0b67d4a7669504425b6057f9249cdf8397c39279 100644
--- a/include/core/SkTInternalLList.h
+++ b/include/core/SkTInternalLList.h
@@ -227,7 +227,7 @@ public:
     void validate() const {
         SkASSERT(!fHead == !fTail);
         Iter iter;
-        for (T* item = iter.init(*this, Iter::kHead_IterStart); NULL != (item = iter.next()); ) {
+        for (T* item = iter.init(*this, Iter::kHead_IterStart); NULL != item; item = iter.next()) {
             SkASSERT(this->isInList(item));
             if (NULL == item->fPrev) {
                 SkASSERT(fHead == item);