Bug 1607984 - P17. Put ParentProcessDocumentChannel behind a pref. r=necko-reviewers,mattwoodrow

We disable it for now, until some remaining failures are sorted out.

Differential Revision: https://phabricator.services.mozilla.com/D71875

modules/libpref/init/StaticPrefList.yaml

@@ -979,6 +979,11 @@
   value: true
   mirror: always
 
+- name: browser.tabs.documentchannel.ppdc
+  type: bool
+  value: false
+  mirror: always
+
 - name: browser.tabs.remote.desktopbehavior
   type: bool
   value: false

netwerk/ipc/DocumentChannel.cpp

@@ -153,6 +153,12 @@ static bool URIUsesDocChannel(nsIURI* aURI) {
 
 bool DocumentChannel::CanUseDocumentChannel(nsDocShellLoadState* aLoadState) {
   MOZ_ASSERT(aLoadState);
+
+  if (XRE_IsParentProcess() &&
+      !StaticPrefs::browser_tabs_documentchannel_ppdc()) {
+    return false;
+  }
+
   // We want to use DocumentChannel if we're using a supported scheme. Sandboxed
   // srcdoc loads break due to failing assertions after changing processes, and
   // non-sandboxed srcdoc loads need to share the same principal object as their