1 files changed, 31 insertions, 0 deletions
diff --git a/dom/fetch/FetchSignal.h b/dom/fetch/FetchSignal.h
index 5bb16b8348..5d2f13c689 100644
--- a/dom/fetch/FetchSignal.h
+++ b/dom/fetch/FetchSignal.h
@@ -13,10 +13,29 @@ namespace mozilla {
 namespace dom {
 
 class FetchController;
+class FetchSignal;
 
 class FetchSignal final : public DOMEventTargetHelper
 {
 public:
+  // This class must be implemented by objects who want to follow a FetchSignal.
+  class Follower
+  {
+  public:
+    virtual void Aborted() = 0;
+
+  protected:
+    virtual ~Follower();
+
+    void
+    Follow(FetchSignal* aSignal);
+
+    void
+    Unfollow();
+
+    RefPtr<FetchSignal> mFollowingSignal;
+  };
+
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(FetchSignal, DOMEventTargetHelper)
 
@@ -33,11 +52,23 @@ public:
 
   IMPL_EVENT_HANDLER(abort);
 
+  void
+  AddFollower(Follower* aFollower);
+
+  void
+  RemoveFollower(Follower* aFollower);
+
+  bool
+  CanAcceptFollower(Follower* aFollower) const;
+
 private:
   ~FetchSignal() = default;
 
   RefPtr<FetchController> mController;
 
+  // Raw pointers. Follower unregisters itself in the DTOR.
+  nsTArray<Follower*> mFollowers;
+
   bool mAborted;
 };