diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index e84e5af..6c7b714 100644
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,23 @@
+2018-11-28  Youenn Fablet  <youenn@apple.com>
+
+        imported/w3c/web-platform-tests/webrtc/RTCPeerConnection-transceivers.https.html is flaky on iOS simulator
+        https://bugs.webkit.org/show_bug.cgi?id=192037
+
+        Reviewed by Eric Carlson.
+
+        The stats report JS map should be created when resolving the stats promise with WebCore RTCStatsReport.
+        But resolving the promise might fail in case of a page being suspended.
+        In that case, no JSRTCStatsReport is created and there is no backing map.
+        Update the code to reflect that.
+        Covered by existing test.
+
+        * Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.cpp:
+        (WebCore::LibWebRTCMediaEndpoint::getStats):
+        * Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.cpp:
+        (WebCore::LibWebRTCStatsCollector::~LibWebRTCStatsCollector):
+        (WebCore::LibWebRTCStatsCollector::OnStatsDelivered):
+        * Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.h:
+
 2018-11-28  Keith Rollin  <krollin@apple.com>
 
         Update generate-{derived,unified}-sources scripts to support generating .xcfilelist files
diff --git a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.cpp b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.cpp
index a9ee827..3acb25c 100644
--- a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.cpp
+++ b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.cpp
@@ -285,13 +285,19 @@
 
 void LibWebRTCMediaEndpoint::getStats(Ref<DeferredPromise>&& promise, WTF::Function<void(rtc::scoped_refptr<LibWebRTCStatsCollector>&&)>&& getStatsFunction)
 {
-    auto collector = LibWebRTCStatsCollector::create([promise = WTFMove(promise), protectedThis = makeRef(*this)](auto&& report) mutable {
+    auto collector = LibWebRTCStatsCollector::create([promise = WTFMove(promise), protectedThis = makeRef(*this)]() mutable -> RefPtr<RTCStatsReport> {
         ASSERT(isMainThread());
-        if (protectedThis->isStopped() || !report)
-            return false;
+        if (protectedThis->isStopped())
+            return nullptr;
 
-        promise->resolve<IDLInterface<RTCStatsReport>>(report.releaseNonNull());
-        return true;
+        auto report = RTCStatsReport::create();
+
+        promise->resolve<IDLInterface<RTCStatsReport>>(report.copyRef());
+
+        // The promise resolution might fail in which case no backing map will be created.
+        if (!report->backingMap())
+            return nullptr;
+        return WTFMove(report);
     });
     LibWebRTCProvider::callOnWebRTCSignalingThread([getStatsFunction = WTFMove(getStatsFunction), collector = WTFMove(collector)]() mutable {
         getStatsFunction(WTFMove(collector));
diff --git a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.cpp b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.cpp
index 8683d73..1ac8378 100644
--- a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.cpp
+++ b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.cpp
@@ -44,7 +44,7 @@
         return;
 
     callOnMainThread([callback = WTFMove(m_callback)]() mutable {
-        callback({ });
+        callback();
     });
 }
 
@@ -384,8 +384,8 @@
 void LibWebRTCStatsCollector::OnStatsDelivered(const rtc::scoped_refptr<const webrtc::RTCStatsReport>& rtcReport)
 {
     callOnMainThread([protectedThis = rtc::scoped_refptr<LibWebRTCStatsCollector>(this), rtcReport] {
-        auto report = RTCStatsReport::create();
-        if (!protectedThis->m_callback(report.copyRef()))
+        auto report = protectedThis->m_callback();
+        if (!report)
             return;
 
         ASSERT(report->backingMap());
diff --git a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.h b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.h
index 8b2a864..253b598 100644
--- a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.h
+++ b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCStatsCollector.h
@@ -42,7 +42,7 @@
 
 class LibWebRTCStatsCollector : public webrtc::RTCStatsCollectorCallback {
 public:
-    using CollectorCallback = WTF::CompletionHandler<bool(RefPtr<RTCStatsReport>&&)>;
+    using CollectorCallback = CompletionHandler<RefPtr<RTCStatsReport>()>;
     static rtc::scoped_refptr<LibWebRTCStatsCollector> create(CollectorCallback&& callback) { return new rtc::RefCountedObject<LibWebRTCStatsCollector>(WTFMove(callback)); }
 
     explicit LibWebRTCStatsCollector(CollectorCallback&&);