Make GetFSRefInternal assume NS_ERROR_FILE_NOT_FOUND when CFURLGetFSRef

returns false.
b=202772; r=ssu, ccarlen; sr=sfraser; a=asa

xpcom/io/nsLocalFileOSX.cpp

@@ -938,11 +938,8 @@ NS_IMETHODIMP nsLocalFile::IsDirectory(PRBool *_retval)
   
   FSRef fsRef;
   nsresult rv = GetFSRefInternal(fsRef, PR_FALSE);
-  // CFURLGetFSRef only returns a Boolean for success,
-  // so we have to assume what the error was. This is
-  // the only probable cause.  
   if (NS_FAILED(rv))
-    return NS_ERROR_FILE_NOT_FOUND;
+    return rv;
     
   FSCatalogInfo catalogInfo;
   OSErr err = ::FSGetCatalogInfo(&fsRef, kFSCatInfoNodeFlags, &catalogInfo,
@@ -961,11 +958,8 @@ NS_IMETHODIMP nsLocalFile::IsFile(PRBool *_retval)
   
   FSRef fsRef;
   nsresult rv = GetFSRefInternal(fsRef, PR_FALSE);
-  // CFURLGetFSRef only returns a Boolean for success,
-  // so we have to assume what the error was. This is
-  // the only probable cause.
   if (NS_FAILED(rv))
-    return NS_ERROR_FILE_NOT_FOUND;
+    return rv;
     
   FSCatalogInfo catalogInfo;
   OSErr err = ::FSGetCatalogInfo(&fsRef, kFSCatInfoNodeFlags, &catalogInfo,
@@ -1900,7 +1894,10 @@ nsresult nsLocalFile::GetFSRefInternal(FSRef& aFSRef, PRBool bForceUpdateCache)
     aFSRef = mCachedFSRef;
     return NS_OK;
   }
-  return NS_ERROR_FAILURE;
+  // CFURLGetFSRef only returns a Boolean for success,
+  // so we have to assume what the error was. This is
+  // the only probable cause.
+  return NS_ERROR_FILE_NOT_FOUND;
 }
 
 nsresult nsLocalFile::GetPathInternal(nsACString& path)