Bug 1646892 - Allow DocumentChannel process switches into the parent process. r=jya,nika

Differential Revision: https://phabricator.services.mozilla.com/D80327

docshell/base/nsDocShellLoadState.h

@@ -50,6 +50,7 @@ class nsDocShellLoadState final {
 
   static nsresult CreateFromPendingChannel(nsIChannel* aPendingChannel,
                                            uint64_t aLoadIdentifier,
+                                           uint64_t aRegistarId,
                                            nsDocShellLoadState** aResult);
 
   static nsresult CreateFromLoadURIOptions(
@@ -230,6 +231,10 @@ class nsDocShellLoadState final {
     return mPendingRedirectedChannel;
   }
 
+  uint64_t GetPendingRedirectChannelRegistrarId() const {
+    return mChannelRegistrarId;
+  }
+
   void SetOriginalURIString(const nsCString& aOriginalURI) {
     mOriginalURIString.emplace(aOriginalURI);
   }
@@ -426,6 +431,11 @@ class nsDocShellLoadState final {
   // when initiating the load.
   mozilla::Maybe<int32_t> mCancelContentJSEpoch;
 
+  // If mPendingRedirectChannel is set, then this is the identifier
+  // that the parent-process equivalent channel has been registered
+  // with using RedirectChannelRegistrar.
+  uint64_t mChannelRegistrarId;
+
   // An identifier to make it possible to examine if two loads are
   // equal, and which browsing context they belong to (see
   // BrowsingContext::{Get, Set}CurrentLoadIdentifier)