From 3efc420b111470236ed9380b26052126f134baff Mon Sep 17 00:00:00 2001
From: Eric Rahm <erahm@mozilla.com>
Date: Mon, 12 Feb 2018 14:54:14 -0800
Subject: [PATCH] Bug 1437693 - Stop warning about unknown content lengths.
 r=bkelly

--HG--
extra : rebase_source : 943658882837ad790542231634d2a24c21906094
---
 dom/fetch/FetchDriver.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dom/fetch/FetchDriver.cpp b/dom/fetch/FetchDriver.cpp
index 2d4ada3b349a..f00ab1029074 100644
--- a/dom/fetch/FetchDriver.cpp
+++ b/dom/fetch/FetchDriver.cpp
@@ -851,8 +851,9 @@ FetchDriver::OnStartRequest(nsIRequest* aRequest,
     ErrorResult result;
     if (response->Headers()->Has(NS_LITERAL_CSTRING("content-encoding"), result) ||
         response->Headers()->Has(NS_LITERAL_CSTRING("transfer-encoding"), result)) {
-      NS_WARNING("Cannot know response Content-Length due to presence of Content-Encoding "
-                 "or Transfer-Encoding headers.");
+      // We cannot trust the content-length when content-encoding or
+      // transfer-encoding are set.  There are many servers which just
+      // get this wrong.
       contentLength = InternalResponse::UNKNOWN_BODY_SIZE;
     }
     MOZ_ASSERT(!result.Failed());