Bug 983504 - Modify constraints for screen sharing. r=bholley,jib

content/media/webrtc/MediaTrackConstraints.h

@@ -42,6 +42,19 @@ public:
         }
       }
     }
+
+    // treat MediaSource special because it's always required
+    mRequired.mMediaSource = mMediaSource;
+
+    if (mMediaSource != dom::MediaSourceEnum::Camera && mAdvanced.WasPassed()) {
+      // iterate through advanced, forcing mediaSource to match "root"
+      auto& array = mAdvanced.Value();
+      for (uint32_t i = 0; i < array.Length(); i++) {
+        if (array[i].mMediaSource == dom::MediaSourceEnum::Camera) {
+          array[i].mMediaSource = mMediaSource;
+        }
+      }
+    }
   }
 protected:
   MediaTrackConstraintSet& Triage(const Kind kind) {
@@ -85,6 +98,9 @@ struct VideoTrackConstraintsN :
     Triage(Kind::Width).mWidth = mWidth;
     Triage(Kind::Height).mHeight = mHeight;
     Triage(Kind::FrameRate).mFrameRate = mFrameRate;
+
+    // treat MediaSource special because it's always required
+    mRequired.mMediaSource = mMediaSource;
   }
 };
 

dom/media/MediaManager.cpp

@@ -310,6 +310,9 @@ VideoDevice::VideoDevice(MediaEngineVideoSource* aSource)
     mHasFacingMode = true;
     mFacingMode = dom::VideoFacingModeEnum::User;
   }
+
+  // dom::MediaSourceEnum::Camera;
+  mMediaSource = aSource->GetMediaSource();
 }
 
 AudioDevice::AudioDevice(MediaEngineAudioSource* aSource)
@@ -361,6 +364,15 @@ MediaDevice::GetFacingMode(nsAString& aFacingMode)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+MediaDevice::GetMediaSource(nsAString& aMediaSource)
+{
+
+  aMediaSource.Assign(NS_ConvertUTF8toUTF16(
+    dom::MediaSourceEnumValues::strings[uint32_t(mMediaSource)].value));
+  return NS_OK;
+}
+
 MediaEngineVideoSource*
 VideoDevice::GetSource()
 {
@@ -714,14 +726,19 @@ static bool SatisfyConstraintSet(const MediaEngineVideoSource *,
                                  const MediaTrackConstraintSet &aConstraints,
                                  nsIMediaDevice &aCandidate)
 {
+  nsString s;
   if (aConstraints.mFacingMode.WasPassed()) {
-    nsString s;
     aCandidate.GetFacingMode(s);
     if (!s.EqualsASCII(dom::VideoFacingModeEnumValues::strings[
         uint32_t(aConstraints.mFacingMode.Value())].value)) {
       return false;
     }
   }
+  aCandidate.GetMediaSource(s);
+  if (!s.EqualsASCII(dom::MediaSourceEnumValues::strings[
+      uint32_t(aConstraints.mMediaSource)].value)) {
+    return false;
+  }
   // TODO: Add more video-specific constraints
   return true;
 }
@@ -742,7 +759,7 @@ template<class SourceType, class ConstraintsType>
 static SourceSet *
   GetSources(MediaEngine *engine,
              ConstraintsType &aConstraints,
-             void (MediaEngine::* aEnumerate)(nsTArray<nsRefPtr<SourceType> >*),
+             void (MediaEngine::* aEnumerate)(dom::MediaSourceEnum, nsTArray<nsRefPtr<SourceType> >*),
              const char* media_device_name = nullptr)
 {
   ScopedDeletePtr<SourceSet> result(new SourceSet);
@@ -753,7 +770,7 @@ static SourceSet *
   SourceSet candidateSet;
   {
     nsTArray<nsRefPtr<SourceType> > sources;
-    (engine->*aEnumerate)(&sources);
+    (engine->*aEnumerate)(aConstraints.mMediaSource, &sources);
     /**
       * We're allowing multiple tabs to access the same camera for parity
       * with Chrome.  See bug 811757 for some of the issues surrounding
@@ -1018,8 +1035,8 @@ public:
     MOZ_ASSERT(mError);
     if (mConstraints.mPicture || IsOn(mConstraints.mVideo)) {
       VideoTrackConstraintsN constraints(GetInvariant(mConstraints.mVideo));
-      ScopedDeletePtr<SourceSet> sources (GetSources(backend, constraints,
-          &MediaEngine::EnumerateVideoDevices));
+      ScopedDeletePtr<SourceSet> sources(GetSources(backend, constraints,
+                               &MediaEngine::EnumerateVideoDevices));
 
       if (!sources->Length()) {
         Fail(NS_LITERAL_STRING("NO_DEVICES_FOUND"));
@@ -1180,8 +1197,8 @@ public:
     if (IsOn(mConstraints.mVideo)) {
       VideoTrackConstraintsN constraints(GetInvariant(mConstraints.mVideo));
       ScopedDeletePtr<SourceSet> s(GetSources(backend, constraints,
-          &MediaEngine::EnumerateVideoDevices,
-          mLoopbackVideoDevice.get()));
+              &MediaEngine::EnumerateVideoDevices,
+              mLoopbackVideoDevice.get()));
       final->MoveElementsFrom(*s);
     }
     if (IsOn(mConstraints.mAudio)) {
@@ -1191,6 +1208,7 @@ public:
           mLoopbackAudioDevice.get()));
       final->MoveElementsFrom(*s);
     }
+
     NS_DispatchToMainThread(new DeviceSuccessCallbackRunnable(mWindowId,
                                                               mSuccess, mError,
                                                               final.forget()));
@@ -1465,6 +1483,15 @@ MediaManager::GetUserMedia(bool aPrivileged,
       onError.forget(), windowID, listener, mPrefs);
   }
 
+  // deny screensharing request if support is disabled
+  if (c.mVideo.IsMediaTrackConstraints() &&
+      !Preferences::GetBool("media.getusermedia.screensharing.enabled", false)) {
+    auto& tc = c.mVideo.GetAsMediaTrackConstraints();
+    if (tc.mMediaSource != dom::MediaSourceEnum::Camera) {
+      return runnable->Denied(NS_LITERAL_STRING("PERMISSION_DENIED"));
+    }
+  }
+
 #ifdef MOZ_B2G_CAMERA
   if (mCameraManager == nullptr) {
     mCameraManager = nsDOMCameraManager::CreateInstance(aWindow);

dom/media/MediaManager.h

@@ -486,6 +486,7 @@ protected:
   nsString mID;
   bool mHasFacingMode;
   dom::VideoFacingModeEnum mFacingMode;
+  dom::MediaSourceEnum mMediaSource;
   nsRefPtr<MediaEngineSource> mSource;
 };
 

dom/media/nsIDOMNavigatorUserMedia.idl

@@ -13,6 +13,7 @@ interface nsIMediaDevice : nsISupports
   readonly attribute DOMString name;
   readonly attribute DOMString id;
   readonly attribute DOMString facingMode;
+  readonly attribute DOMString mediaSource;
 };
 
 [scriptable, function, uuid(24544878-d35e-4962-8c5f-fb84e97bdfee)]

dom/webidl/Constraints.webidl

@@ -14,6 +14,12 @@ enum VideoFacingModeEnum {
     "right"
 };
 
+enum MediaSourceEnum {
+    "camera",
+    "screen",
+    "application"
+};
+
 dictionary ConstrainLongRange {
     long min = -2147483647; // +1 works around windows compiler bug
     long max = 2147483647;

dom/webidl/MediaTrackConstraintSet.webidl

@@ -13,17 +13,20 @@ enum SupportedVideoConstraints {
     "width",
     "height",
     "frameRate",
+    "mediaSource"
 };
 
 enum SupportedAudioConstraints {
     "other"
 };
 
+
 dictionary MediaTrackConstraintSet {
     ConstrainLongRange width;
     ConstrainLongRange height;
     ConstrainDoubleRange frameRate;
     ConstrainVideoFacingMode facingMode;
+    ConstrainMediaSource mediaSource = "camera";
 };
 
 // TODO: Bug 995352 can't nest unions
@@ -31,5 +34,8 @@ dictionary MediaTrackConstraintSet {
 //typedef (double or ConstrainDoubleRange) ConstrainDouble;
 
 typedef VideoFacingModeEnum ConstrainVideoFacingMode;
+typedef MediaSourceEnum ConstrainMediaSource;
+
 // TODO: Bug 767924 sequences in unions
 //typedef (VideoFacingModeEnum or sequence<VideoFacingModeEnum>) ConstrainVideoFacingMode;
+//typedef (MediaSourceEnum or sequence<MediaSourceEnum>) ConstrainMediaSource;

modules/libpref/src/init/all.js

@@ -357,6 +357,12 @@ pref("media.navigator.enabled", true);
 #endif
 #endif
 
+// do not enable screensharing before addressing security concerns: Bug 1035577
+// do not enable screensharing before implementing app/window sharing: Bug 1036653
+// do not enable screensharing before source constraints are finalized: Bug 1033885
+// do not enable screensharing before UX is ready: Bug 1035577
+pref("media.getusermedia.screensharing.enabled", false);
+
 // TextTrack support
 pref("media.webvtt.enabled", true);
 pref("media.webvtt.regions.enabled", false);