diff --git a/layout/generic/nsTextTransformer.cpp b/layout/generic/nsTextTransformer.cpp
index ebd68c9d6371..fc17f13b81f2 100644
--- a/layout/generic/nsTextTransformer.cpp
+++ b/layout/generic/nsTextTransformer.cpp
@@ -1492,7 +1492,6 @@ nsTextTransformer::DoArabicShaping(PRUnichar* aText,
   PRBool isVisual = mPresContext->IsVisualMode();
 
   nsAutoString buf;
-  buf.SetLength(aTextLength);
   if (!EnsureStringLength(buf, aTextLength)) {
     // no way to signal OOM
     aTextLength = 0;
diff --git a/xpcom/string/public/nsReadableUtils.h b/xpcom/string/public/nsReadableUtils.h
index fee6741d6a59..4a7c22429bf4 100755
--- a/xpcom/string/public/nsReadableUtils.h
+++ b/xpcom/string/public/nsReadableUtils.h
@@ -371,13 +371,8 @@ CompareUTF8toUTF16(const nsASingleFragmentCString& aUTF8String,
 NS_COM void
 AppendUCS4ToUTF16(const PRUint32 aSource, nsAString& aDest);
 
-inline PRBool EnsureStringLength(nsAString &aStr, PRUint32 aLen)
-{
-    aStr.SetLength(aLen);
-    return (aStr.Length() == aLen);
-}
-
-inline PRBool EnsureStringLength(nsACString &aStr, PRUint32 aLen)
+template<class T>
+inline PRBool EnsureStringLength(T& aStr, PRUint32 aLen)
 {
     aStr.SetLength(aLen);
     return (aStr.Length() == aLen);