Bug 1128379 - improve error handling in MediaKeys::CreateSession. r=bz

dom/bindings/Bindings.conf

@@ -633,6 +633,10 @@ DOMInterfaces = {
     'headerFile': 'nsIMediaList.h',
 },
 
+'MediaKeys' : {
+    'implicitJSContext': [ 'createSession']
+},
+
 'MediaKeyStatusMap' : {
     'implicitJSContext': [ 'size', 'get', 'has' ]
 },

dom/media/eme/MediaKeySession.cpp

@@ -36,7 +36,8 @@ NS_IMPL_RELEASE_INHERITED(MediaKeySession, DOMEventTargetHelper)
 // unique token.
 static uint32_t sMediaKeySessionNum = 0;
 
-MediaKeySession::MediaKeySession(nsPIDOMWindow* aParent,
+MediaKeySession::MediaKeySession(JSContext* aCx,
+                                 nsPIDOMWindow* aParent,
                                  MediaKeys* aKeys,
                                  const nsAString& aKeySystem,
                                  SessionType aSessionType,
@@ -48,9 +49,12 @@ MediaKeySession::MediaKeySession(nsPIDOMWindow* aParent,
   , mToken(sMediaKeySessionNum++)
   , mIsClosed(false)
   , mUninitialized(true)
-  , mKeyStatusMap(new MediaKeyStatusMap(aParent))
+  , mKeyStatusMap(new MediaKeyStatusMap(aCx, aParent, aRv))
 {
   MOZ_ASSERT(aParent);
+  if (aRv.Failed()) {
+    return;
+  }
   mClosed = mKeys->MakePromise(aRv);
 }
 

dom/media/eme/MediaKeySession.h

@@ -39,7 +39,8 @@ public:
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(MediaKeySession,
                                            DOMEventTargetHelper)
 public:
-  MediaKeySession(nsPIDOMWindow* aParent,
+  MediaKeySession(JSContext* aCx,
+                  nsPIDOMWindow* aParent,
                   MediaKeys* aKeys,
                   const nsAString& aKeySystem,
                   SessionType aSessionType,

dom/media/eme/MediaKeyStatusMap.cpp

@@ -37,20 +37,15 @@ NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(MediaKeyStatusMap)
   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mMap)
 NS_IMPL_CYCLE_COLLECTION_TRACE_END
 
-MediaKeyStatusMap::MediaKeyStatusMap(nsPIDOMWindow* aParent)
+MediaKeyStatusMap::MediaKeyStatusMap(JSContext* aCx,
+                                     nsPIDOMWindow* aParent,
+                                     ErrorResult& aRv)
   : mParent(aParent)
   , mUpdateError(NS_OK)
 {
-  AutoJSAPI jsapi;
+  mMap = JS::NewMapObject(aCx);
-  if (NS_WARN_IF(!jsapi.Init(aParent))) {
-    mUpdateError = NS_ERROR_FAILURE;
-    return;
-  }
-
-  JSContext* cx = jsapi.cx();
-  mMap = JS::NewMapObject(cx);
   if (NS_WARN_IF(!mMap)) {
-    mUpdateError = NS_ERROR_FAILURE;
+    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
   }
 }
 
@@ -209,7 +204,7 @@ nsresult
 MediaKeyStatusMap::UpdateInternal(const nsTArray<CDMCaps::KeyStatus>& keys)
 {
   AutoJSAPI jsapi;
-  if (!mMap || NS_WARN_IF(!jsapi.Init(mParent))) {
+  if (NS_WARN_IF(!jsapi.Init(mParent))) {
     return NS_ERROR_FAILURE;
   }
 

dom/media/eme/MediaKeyStatusMap.h

@@ -30,7 +30,9 @@ public:
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(MediaKeyStatusMap)
 
 public:
-  explicit MediaKeyStatusMap(nsPIDOMWindow* aParent);
+  explicit MediaKeyStatusMap(JSContext* aCx,
+                             nsPIDOMWindow* aParent,
+                             ErrorResult& aRv);
 
 protected:
   ~MediaKeyStatusMap();

dom/media/eme/MediaKeys.cpp

@@ -359,15 +359,21 @@ MediaKeys::OnCDMCreated(PromiseId aId, const nsACString& aNodeId)
 }
 
 already_AddRefed<MediaKeySession>
-MediaKeys::CreateSession(SessionType aSessionType,
+MediaKeys::CreateSession(JSContext* aCx,
+                         SessionType aSessionType,
                          ErrorResult& aRv)
 {
-  nsRefPtr<MediaKeySession> session = new MediaKeySession(GetParentObject(),
+  nsRefPtr<MediaKeySession> session = new MediaKeySession(aCx,
+                                                          GetParentObject(),
                                                           this,
                                                           mKeySystem,
                                                           aSessionType,
                                                           aRv);
 
+  if (aRv.Failed()) {
+    return nullptr;
+  }
+
   // Add session to the set of sessions awaiting their sessionId being ready.
   mPendingSessions.Put(session->Token(), session);
 

dom/media/eme/MediaKeys.h

@@ -65,7 +65,8 @@ public:
   void GetKeySystem(nsString& retval) const;
 
   // JavaScript: MediaKeys.createSession()
-  already_AddRefed<MediaKeySession> CreateSession(SessionType aSessionType,
+  already_AddRefed<MediaKeySession> CreateSession(JSContext* aCx,
+                                                  SessionType aSessionType,
                                                   ErrorResult& aRv);
 
   // JavaScript: MediaKeys.SetServerCertificate()