3 files changed, 34 insertions, 14 deletions
diff --git a/dom/xhr/XMLHttpRequest.cpp b/dom/xhr/XMLHttpRequest.cpp
index be94267d63..8807c5515a 100644
--- a/dom/xhr/XMLHttpRequest.cpp
+++ b/dom/xhr/XMLHttpRequest.cpp
@@ -7,7 +7,9 @@
 #include "XMLHttpRequest.h"
 #include "XMLHttpRequestMainThread.h"
 #include "XMLHttpRequestWorker.h"
+#include "mozilla/BasePrincipal.h"
 #include "mozilla/Logging.h"
+#include "mozilla/StaticPrefs_network.h"
 #include "mozilla/net/CookieJarSettings.h"
 
 mozilla::LazyLogModule gXMLHttpRequestLog("XMLHttpRequest");
@@ -21,15 +23,16 @@ already_AddRefed<XMLHttpRequest> XMLHttpRequest::Constructor(
   if (NS_IsMainThread()) {
     nsCOMPtr<nsIGlobalObject> global =
         do_QueryInterface(aGlobal.GetAsSupports());
-    nsCOMPtr<nsIScriptObjectPrincipal> principal =
+    nsCOMPtr<nsIScriptObjectPrincipal> scriptPrincipal =
         do_QueryInterface(aGlobal.GetAsSupports());
-    if (!global || !principal) {
+    if (!global || !scriptPrincipal) {
       aRv.Throw(NS_ERROR_FAILURE);
       return nullptr;
     }
 
     nsCOMPtr<nsICookieJarSettings> cookieJarSettings;
     nsCOMPtr<nsPIDOMWindowInner> window = do_QueryInterface(global);
+    nsCOMPtr<nsIPrincipal> principal = scriptPrincipal->GetPrincipal();
     if (window) {
       Document* document = window->GetExtantDoc();
       if (NS_WARN_IF(!document)) {
@@ -40,13 +43,21 @@ already_AddRefed<XMLHttpRequest> XMLHttpRequest::Constructor(
       cookieJarSettings = document->CookieJarSettings();
     } else {
       // We are here because this is a sandbox.
-      cookieJarSettings =
-          net::CookieJarSettings::Create(principal->GetPrincipal());
+      cookieJarSettings = net::CookieJarSettings::Create(principal);
     }
 
     RefPtr<XMLHttpRequestMainThread> req = new XMLHttpRequestMainThread(global);
-    req->Construct(principal->GetPrincipal(), cookieJarSettings, false);
-    req->InitParameters(aParams.mMozAnon, aParams.mMozSystem);
+    req->Construct(principal, cookieJarSettings, false);
+
+    bool isAnon = false;
+    if (aParams.mMozAnon.WasPassed()) {
+      isAnon = aParams.mMozAnon.Value();
+    } else {
+      isAnon =
+          StaticPrefs::network_fetch_systemDefaultsToOmittingCredentials() &&
+          (aParams.mMozSystem || principal->IsSystemPrincipal());
+    }
+    req->InitParameters(isAnon, aParams.mMozSystem);
     return req.forget();
   }
 
diff --git a/dom/xhr/XMLHttpRequestMainThread.cpp b/dom/xhr/XMLHttpRequestMainThread.cpp
index ace26f296f..e18800e24a 100644
--- a/dom/xhr/XMLHttpRequestMainThread.cpp
+++ b/dom/xhr/XMLHttpRequestMainThread.cpp
@@ -228,12 +228,19 @@ struct DebugWorkerRefs {
     (((const std::ostringstream&)(std::ostringstream() << stuff)) \
          .str())  // NOLINT
 
-#  define DEBUG_WORKERREFS \
-    DebugWorkerRefs MOZ_UNIQUE_VAR(debugWR__)(*this, __func__)
+#  if 1  // Disabling because bug 1855699
+#    define DEBUG_WORKERREFS void()
+#    define DEBUG_WORKERREFS1(x) void()
+#  else
 
-#  define DEBUG_WORKERREFS1(x)                 \
-    DebugWorkerRefs MOZ_UNIQUE_VAR(debugWR__)( \
-        *this, STREAM_STRING(__func__ << ": " << x))  // NOLINT
+#    define DEBUG_WORKERREFS \
+      DebugWorkerRefs MOZ_UNIQUE_VAR(debugWR__)(*this, __func__)
+
+#    define DEBUG_WORKERREFS1(x)                 \
+      DebugWorkerRefs MOZ_UNIQUE_VAR(debugWR__)( \
+          *this, STREAM_STRING(__func__ << ": " << x))  // NOLINT
+
+#  endif
 
 #else
 #  define DEBUG_WORKERREFS void()
diff --git a/dom/xhr/XMLHttpRequestWorker.cpp b/dom/xhr/XMLHttpRequestWorker.cpp
index 7fdfa8fee9..67cba876db 100644
--- a/dom/xhr/XMLHttpRequestWorker.cpp
+++ b/dom/xhr/XMLHttpRequestWorker.cpp
@@ -1388,10 +1388,12 @@ already_AddRefed<XMLHttpRequest> XMLHttpRequestWorker::Construct(
       new XMLHttpRequestWorker(workerPrivate, global);
 
   if (workerPrivate->XHRParamsAllowed()) {
-    if (aParams.mMozSystem)
+    if (aParams.mMozSystem) {
       xhr->mMozAnon = true;
-    else
-      xhr->mMozAnon = aParams.mMozAnon;
+    } else {
+      xhr->mMozAnon =
+          aParams.mMozAnon.WasPassed() ? aParams.mMozAnon.Value() : false;
+    }
     xhr->mMozSystem = aParams.mMozSystem;
   }