Reduce string copying from nsGenericHTMLElement::GetHrefURIForAnchors (bug 267506). r+sr=jst.

content/base/src/nsContentUtils.cpp

@@ -1538,11 +1538,8 @@ nsContentUtils::NewURIWithDocumentCharset(nsIURI** aResult,
                                           nsIDocument* aDocument,
                                           nsIURI* aBaseURI)
 {
-  nsCAutoString originCharset;
-  if (aDocument)
-    originCharset = aDocument->GetDocumentCharacterSet();
-
-  return NS_NewURI(aResult, NS_ConvertUCS2toUTF8(aSpec), originCharset.get(),
+  return NS_NewURI(aResult, aSpec,
+                   aDocument ? aDocument->GetDocumentCharacterSet().get() : nsnull,
                    aBaseURI, sIOService);
 }
 

content/html/content/src/nsGenericHTMLElement.cpp

@@ -1583,16 +1583,16 @@ nsGenericHTMLElement::GetHrefURIForAnchors(nsIURI** aURI)
   // nsHTMLStyleElement.
 
   // Get href= attribute (relative URI).
-  nsAutoString relURISpec;
 
-  if (NS_CONTENT_ATTR_HAS_VALUE ==
-      GetAttr(kNameSpaceID_None, nsHTMLAtoms::href, relURISpec)) {
+  // We use the nsAttrValue's copy of the URI string to avoid copying.
+  const nsAttrValue* attr = mAttrsAndChildren.GetAttr(nsHTMLAtoms::href);
+  if (attr) {
     // Get base URI.
     nsCOMPtr<nsIURI> baseURI = GetBaseURI();
 
     // Get absolute URI.
     nsresult rv = nsContentUtils::NewURIWithDocumentCharset(aURI,
-                                                            relURISpec,
+                                                            attr->GetStringValue(),
                                                             GetOwnerDoc(),
                                                             baseURI);
     if (NS_FAILED(rv)) {