Bug 1582124 - Break Document cycles when they are destroyed r=smaug

This patch nulls out a Document's promises when it is destroyed to break cycles going through them and ensure Documents are cleaned up sooner.

Differential Revision: https://phabricator.services.mozilla.com/D46286

--HG--
extra : moz-landing-system : lando

dom/base/Document.cpp

@@ -10581,6 +10581,10 @@ void Document::Destroy() {
   // leak-fixing if we fix nsDocumentViewer to do cycle-collection, but
   // tearing down all those frame trees right now is the right thing to do.
   mExternalResourceMap.Shutdown();
+
+  // Manually break cycles via promise's global object pointer.
+  mReadyForIdle = nullptr;
+  mOrientationPendingPromise = nullptr;
 }
 
 void Document::RemovedFromDocShell() {
@@ -12615,6 +12619,11 @@ already_AddRefed<nsIURI> Document::GetMozDocumentURIIfNotForErrorPages() {
 }
 
 Promise* Document::GetDocumentReadyForIdle(ErrorResult& aRv) {
+  if (mIsGoingAway) {
+    aRv.Throw(NS_ERROR_NOT_AVAILABLE);
+    return nullptr;
+  }
+
   if (!mReadyForIdle) {
     nsIGlobalObject* global = GetScopeObject();
     if (!global) {
@@ -13815,8 +13824,17 @@ bool Document::FullscreenEnabled(CallerType aCallerType) {
   return !GetFullscreenError(this, aCallerType);
 }
 
-void Document::SetOrientationPendingPromise(Promise* aPromise) {
+void Document::ClearOrientationPendingPromise() {
+  mOrientationPendingPromise = nullptr;
+}
+
+bool Document::SetOrientationPendingPromise(Promise* aPromise) {
+  if (mIsGoingAway) {
+    return false;
+  }
+
   mOrientationPendingPromise = aPromise;
+  return true;
 }
 
 static void DispatchPointerLockChange(Document* aTarget) {

dom/base/Document.h

@@ -2263,7 +2263,8 @@ class Document : public nsINode,
   OrientationType CurrentOrientationType() const {
     return mCurrentOrientationType;
   }
-  void SetOrientationPendingPromise(Promise* aPromise);
+  void ClearOrientationPendingPromise();
+  bool SetOrientationPendingPromise(Promise* aPromise);
   Promise* GetOrientationPendingPromise() const {
     return mOrientationPendingPromise;
   }

dom/base/ScreenOrientation.cpp

@@ -170,14 +170,14 @@ ScreenOrientation::LockOrientationTask::Run() {
   if (mDocument->Hidden()) {
     // Active orientation lock is not the document's orientation lock.
     mPromise->MaybeResolveWithUndefined();
-    mDocument->SetOrientationPendingPromise(nullptr);
+    mDocument->ClearOrientationPendingPromise();
     return NS_OK;
   }
 
   if (mOrientationLock == hal::eScreenOrientation_None) {
     mScreenOrientation->UnlockDeviceOrientation();
     mPromise->MaybeResolveWithUndefined();
-    mDocument->SetOrientationPendingPromise(nullptr);
+    mDocument->ClearOrientationPendingPromise();
     return NS_OK;
   }
 
@@ -190,7 +190,7 @@ ScreenOrientation::LockOrientationTask::Run() {
 
   if (NS_WARN_IF(!result)) {
     mPromise->MaybeReject(NS_ERROR_UNEXPECTED);
-    mDocument->SetOrientationPendingPromise(nullptr);
+    mDocument->ClearOrientationPendingPromise();
     return NS_OK;
   }
 
@@ -199,7 +199,7 @@ ScreenOrientation::LockOrientationTask::Run() {
        mDocument->CurrentOrientationAngle() == 0)) {
     // Orientation lock will not cause an orientation change.
     mPromise->MaybeResolveWithUndefined();
-    mDocument->SetOrientationPendingPromise(nullptr);
+    mDocument->ClearOrientationPendingPromise();
   }
 
   return NS_OK;
@@ -256,7 +256,7 @@ static inline void AbortOrientationPromises(nsIDocShell* aDocShell) {
     Promise* promise = doc->GetOrientationPendingPromise();
     if (promise) {
       promise->MaybeReject(NS_ERROR_DOM_ABORT_ERR);
-      doc->SetOrientationPendingPromise(nullptr);
+      doc->ClearOrientationPendingPromise();
     }
   }
 
@@ -325,7 +325,10 @@ already_AddRefed<Promise> ScreenOrientation::LockInternal(
   rootShell->SetOrientationLock(aOrientation);
   AbortOrientationPromises(rootShell);
 
-  doc->SetOrientationPendingPromise(p);
+  if (!doc->SetOrientationPendingPromise(p)) {
+    p->MaybeReject(NS_ERROR_DOM_SECURITY_ERR);
+    return p.forget();
+  }
 
   nsCOMPtr<nsIRunnable> lockOrientationTask = new LockOrientationTask(
       this, p, aOrientation, doc, perm == FULLSCREEN_LOCK_ALLOWED);
@@ -553,7 +556,7 @@ ScreenOrientation::DispatchChangeEventAndResolvePromise() {
           Promise* pendingPromise = doc->GetOrientationPendingPromise();
           if (pendingPromise) {
             pendingPromise->MaybeResolveWithUndefined();
-            doc->SetOrientationPendingPromise(nullptr);
+            doc->ClearOrientationPendingPromise();
           }
         }
       });