Bug 1732410 wait for focus before proceeding for enumerateDevices() P…

…romises r=jib,nika

w3c/mediacapture-main#574

Focus on browser chrome widgets is accepted provided the tab is fully active
and foreground.
w3c/mediacapture-main#752 (comment)

Differential Revision: https://phabricator.services.mozilla.com/D127051

docshell/base/BrowsingContext.cpp

@@ -33,6 +33,7 @@
 #include "mozilla/dom/HTMLIFrameElement.h"
 #include "mozilla/dom/Location.h"
 #include "mozilla/dom/LocationBinding.h"
+#include "mozilla/dom/MediaDevices.h"
 #include "mozilla/dom/PopupBlocker.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/SessionStorageManager.h"
@@ -2930,14 +2931,19 @@ void BrowsingContext::DidSet(FieldIndex<IDX_IsActiveBrowserWindowInternal>,
     if (RefPtr<Document> doc = aContext->GetExtantDocument()) {
       doc->UpdateDocumentStates(NS_DOCUMENT_STATE_WINDOW_INACTIVE, true);
 
+      RefPtr<nsPIDOMWindowInner> win = doc->GetInnerWindow();
+      RefPtr<MediaDevices> devices;
+      if (isActivateEvent && (devices = win->GetExtantMediaDevices())) {
+        devices->BrowserWindowBecameActive();
+      }
+
       if (XRE_IsContentProcess() &&
           (!aContext->GetParent() || !aContext->GetParent()->IsInProcess())) {
         // Send the inner window an activate/deactivate event if
         // the context is the top of a sub-tree of in-process
         // contexts.
         nsContentUtils::DispatchEventOnlyToChrome(
-            doc, doc->GetWindow()->GetCurrentInnerWindow(),
-            isActivateEvent ? u"activate"_ns : u"deactivate"_ns,
+            doc, win, isActivateEvent ? u"activate"_ns : u"deactivate"_ns,
             CanBubble::eYes, Cancelable::eYes, nullptr);
       }
     }

dom/base/Navigator.h

@@ -178,6 +178,7 @@ class Navigator final : public nsISupports, public nsWrapperCache {
   already_AddRefed<LegacyMozTCPSocket> MozTCPSocket();
   network::Connection* GetConnection(ErrorResult& aRv);
   MediaDevices* GetMediaDevices(ErrorResult& aRv);
+  MediaDevices* GetExtantMediaDevices() const { return mMediaDevices; };
 
   void GetGamepads(nsTArray<RefPtr<Gamepad>>& aGamepads, ErrorResult& aRv);
   GamepadServiceTest* RequestGamepadServiceTest();

dom/base/nsGlobalWindowInner.cpp

@@ -137,6 +137,7 @@
 #include "mozilla/dom/LocalStorage.h"
 #include "mozilla/dom/LocalStorageCommon.h"
 #include "mozilla/dom/Location.h"
+#include "mozilla/dom/MediaDevices.h"
 #include "mozilla/dom/MediaKeys.h"
 #include "mozilla/dom/NavigatorBinding.h"
 #include "mozilla/dom/Nullable.h"
@@ -2310,6 +2311,10 @@ Navigator* nsPIDOMWindowInner::Navigator() {
   return mNavigator;
 }
 
+MediaDevices* nsPIDOMWindowInner::GetExtantMediaDevices() const {
+  return mNavigator ? mNavigator->GetExtantMediaDevices() : nullptr;
+}
+
 VisualViewport* nsGlobalWindowInner::VisualViewport() {
   if (!mVisualViewport) {
     mVisualViewport = new mozilla::dom::VisualViewport(this);
@@ -5570,6 +5575,10 @@ void nsGlobalWindowInner::Resume(bool aIncludeSubWindows) {
     mAudioContexts[i]->ResumeFromChrome();
   }
 
+  if (RefPtr<MediaDevices> devices = GetExtantMediaDevices()) {
+    devices->WindowResumed();
+  }
+
   mTimeoutManager->Resume();
 
   ResumeIdleRequests();
@@ -5721,6 +5730,13 @@ void nsGlobalWindowInner::SyncStateFromParentWindow() {
   }
 }
 
+void nsGlobalWindowInner::UpdateBackgroundState() {
+  if (RefPtr<MediaDevices> devices = GetExtantMediaDevices()) {
+    devices->BackgroundStateChanged();
+  }
+  mTimeoutManager->UpdateBackgroundState();
+}
+
 template <typename Method, typename... Args>
 CallState nsGlobalWindowInner::CallOnInProcessDescendantsInternal(
     BrowsingContext* aBrowsingContext, bool aChildOnly, Method aMethod,

dom/base/nsGlobalWindowInner.h

@@ -325,6 +325,12 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   virtual bool IsFrozen() const override;
   void SyncStateFromParentWindow();
 
+  // Called on the current inner window of a browsing context when its
+  // background state changes according to selected tab or visibility of the
+  // browser window.  Used with Suspend()/Resume() or Freeze()/Thaw() because
+  // background state may change while the inner window is not current.
+  void UpdateBackgroundState();
+
   mozilla::dom::DebuggerNotificationManager*
   GetOrCreateDebuggerNotificationManager() override;
 

dom/base/nsGlobalWindowOuter.cpp

@@ -6757,7 +6757,7 @@ void nsGlobalWindowOuter::SetIsBackground(bool aIsBackground) {
   nsGlobalWindowInner* inner = GetCurrentInnerWindowInternal();
 
   if (inner && changed) {
-    inner->mTimeoutManager->UpdateBackgroundState();
+    inner->UpdateBackgroundState();
   }
 
   if (aIsBackground) {

dom/base/nsPIDOMWindow.h

@@ -62,6 +62,7 @@ class DocGroup;
 class Document;
 class Element;
 class Location;
+class MediaDevices;
 class MediaKeys;
 class Navigator;
 class Performance;
@@ -577,6 +578,7 @@ class nsPIDOMWindowInner : public mozIDOMWindow {
   uint32_t GetMarkedCCGeneration() { return mMarkedCCGeneration; }
 
   mozilla::dom::Navigator* Navigator();
+  mozilla::dom::MediaDevices* GetExtantMediaDevices() const;
   virtual mozilla::dom::Location* Location() = 0;
 
   virtual nsresult GetControllers(nsIControllers** aControllers) = 0;

dom/media/MediaDevices.cpp

@@ -5,6 +5,7 @@
 #include "mozilla/dom/MediaDevices.h"
 
 #include "AudioDeviceInfo.h"
+#include "mozilla/dom/BrowsingContext.h"
 #include "mozilla/dom/Document.h"
 #include "mozilla/dom/MediaStreamBinding.h"
 #include "mozilla/dom/MediaDeviceInfo.h"
@@ -139,10 +140,39 @@ already_AddRefed<Promise> MediaDevices::EnumerateDevices(ErrorResult& aRv) {
   if (NS_WARN_IF(aRv.Failed())) {
     return nullptr;
   }
+  mPendingEnumerateDevicesPromises.AppendElement(p);
+  MaybeResumeDeviceExposure();
+  return p.forget();
+}
+
+void MediaDevices::MaybeResumeDeviceExposure() {
+  if (mPendingEnumerateDevicesPromises.IsEmpty()) {
+    return;
+  }
+  nsPIDOMWindowInner* window = GetOwner();
+  if (!window || !window->IsFullyActive()) {
+    return;
+  }
+  BrowsingContext* bc = window->GetBrowsingContext();
+  if (!bc->IsActive() ||                  // not foreground tab
+      !bc->GetIsActiveBrowserWindow()) {  // browser window does not have focus
+    return;
+  }
+
+  auto pending = std::move(mPendingEnumerateDevicesPromises);
+  for (auto& promise : pending) {
+    ResumeEnumerateDevices(std::move(promise));
+  }
+}
+
+void MediaDevices::ResumeEnumerateDevices(RefPtr<Promise> aPromise) {
+  nsCOMPtr<nsPIDOMWindowInner> window = GetOwner();
+  MOZ_ASSERT(window, "Fully active document should have window");
   RefPtr<MediaDevices> self(this);
-  MediaManager::Get()->EnumerateDevices(owner)->Then(
+  MediaManager::Get()->EnumerateDevices(window)->Then(
       GetCurrentSerialEventTarget(), __func__,
-      [this, self, p](RefPtr<MediaManager::MediaDeviceSetRefCnt>&& aDevices) {
+      [this, self,
+       aPromise](RefPtr<MediaManager::MediaDeviceSetRefCnt>&& aDevices) {
         nsPIDOMWindowInner* window = GetWindowIfCurrent();
         if (!window) {
           return;  // Leave Promise pending after navigation by design.
@@ -189,16 +219,15 @@ already_AddRefed<Promise> MediaDevices::EnumerateDevices(ErrorResult& aRv) {
           infos.AppendElement(MakeRefPtr<MediaDeviceInfo>(
               device->mID, device->mKind, label, device->mGroupID));
         }
-        p->MaybeResolve(std::move(infos));
+        aPromise->MaybeResolve(std::move(infos));
       },
-      [this, self, p](const RefPtr<MediaMgrError>& error) {
+      [this, self, aPromise](const RefPtr<MediaMgrError>& error) {
         nsPIDOMWindowInner* window = GetWindowIfCurrent();
         if (!window) {
           return;  // Leave Promise pending after navigation by design.
         }
-        error->Reject(p);
+        error->Reject(aPromise);
       });
-  return p.forget();
 }
 
 already_AddRefed<Promise> MediaDevices::GetDisplayMedia(
@@ -479,7 +508,10 @@ RefPtr<MediaDevices::SinkInfoPromise> MediaDevices::GetSinkDevice(
           });
 }
 
-NS_IMPL_ISUPPORTS_INHERITED0(MediaDevices, DOMEventTargetHelper)
+NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(MediaDevices,
+                                               DOMEventTargetHelper)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(MediaDevices, DOMEventTargetHelper,
+                                   mPendingEnumerateDevicesPromises)
 
 void MediaDevices::OnDeviceChange() {
   MOZ_ASSERT(NS_IsMainThread());

dom/media/MediaDevices.h

@@ -39,6 +39,7 @@ class MediaDevices final : public DOMEventTargetHelper {
   explicit MediaDevices(nsPIDOMWindowInner* aWindow);
 
   NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(MediaDevices, DOMEventTargetHelper)
 
   JSObject* WrapObject(JSContext* cx,
                        JS::Handle<JSObject*> aGivenProto) override;
@@ -79,14 +80,21 @@ class MediaDevices final : public DOMEventTargetHelper {
   void EventListenerAdded(nsAtom* aType) override;
   using DOMEventTargetHelper::EventListenerAdded;
 
+  void BackgroundStateChanged() { MaybeResumeDeviceExposure(); }
+  void WindowResumed() { MaybeResumeDeviceExposure(); }
+  void BrowserWindowBecameActive() { MaybeResumeDeviceExposure(); }
+
  private:
   class GumResolver;
   class EnumDevResolver;
   class GumRejecter;
 
   virtual ~MediaDevices();
+  void MaybeResumeDeviceExposure();
+  void ResumeEnumerateDevices(RefPtr<Promise> aPromise);
 
   nsTHashSet<nsString> mExplicitlyGrantedAudioOutputIds;
+  nsTArray<RefPtr<Promise>> mPendingEnumerateDevicesPromises;
   nsCOMPtr<nsITimer> mFuzzTimer;
 
   // Connect/Disconnect on main thread only

testing/web-platform/mozilla/meta/mediacapture-streams/enumerateDevices-in-background.https.html.ini

@@ -1,5 +1,3 @@
 [enumerateDevices-in-background.https.html]
   disabled:
     if buildapp != 'browser': uses Firefox-for-Desktop specific API
-  [enumerateDevices in background]
-    expected: FAIL