Bug 1152381 - implement mediaDevices.getSupportedConstraints. r=smaug, r=jesup

dom/media/MediaDevices.cpp

@@ -7,6 +7,7 @@
 #include "mozilla/dom/MediaDevicesBinding.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/MediaManager.h"
+#include "MediaTrackConstraints.h"
 #include "nsIEventTarget.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIPermissionManager.h"

dom/media/MediaDevices.h

@@ -16,6 +16,7 @@ namespace dom {
 
 class Promise;
 struct MediaStreamConstraints;
+struct MediaTrackSupportedConstraints;
 
 #define MOZILLA_DOM_MEDIADEVICES_IMPLEMENTATION_IID \
 { 0x2f784d8a, 0x7485, 0x4280, \
@@ -32,6 +33,9 @@ public:
 
   JSObject* WrapObject(JSContext* cx, JS::Handle<JSObject*> aGivenProto) override;
 
+  // No code needed, as MediaTrackSupportedConstraints members default to true.
+  void GetSupportedConstraints(MediaTrackSupportedConstraints& aResult) {};
+
   already_AddRefed<Promise>
   GetUserMedia(const MediaStreamConstraints& aConstraints, ErrorResult &aRv);
 

dom/media/tests/mochitest/test_getUserMedia_constraints.html

@@ -65,12 +65,40 @@ var tests = [
     error: null },
 ];
 
+var mustSupport = [
+  'width', 'height', 'frameRate', 'facingMode', 'deviceId',
+// Yet to add:
+//  'aspectRatio', 'frameRate', 'volume', 'sampleRate', 'sampleSize',
+//  'echoCancellation', 'latency', 'groupId'
+
+  // http://fluffy.github.io/w3c-screen-share/#screen-based-video-constraints
+  // OBE by http://w3c.github.io/mediacapture-screen-share
+  'mediaSource',
+
+  // Experimental https://bugzilla.mozilla.org/show_bug.cgi?id=1131568#c3
+  'browserWindow', 'scrollWithPage',
+];
+
 /**
  * Starts the test run by running through each constraint
  * test by verifying that the right resolution and rejection is fired.
  */
 
 runTest(function() {
+
+  // Check supported constraints first.
+  var dict = navigator.mediaDevices.getSupportedConstraints();
+  var supported = Object.keys(dict);
+
+  mustSupport.forEach(key => ok(supported.includes(key) && dict[key],
+                                "Supports " + key));
+
+  var unexpected = supported.filter(key => !mustSupport.includes(key));
+  is(unexpected.length, 0,
+     "Unexpected support (please update test): " + unexpected);
+
+  // Run constraint tests
+
   var p = new Promise(resolve => SpecialPowers.pushPrefEnv({
       set : [ ['media.getusermedia.browser.enabled', false],
               ['media.getusermedia.screensharing.enabled', false] ]

dom/media/webrtc/MediaTrackConstraints.h

@@ -10,6 +10,7 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/dom/MediaStreamTrackBinding.h"
 #include "mozilla/dom/MediaTrackConstraintSetBinding.h"
+#include "mozilla/dom/MediaTrackSupportedConstraintsBinding.h"
 
 namespace mozilla {
 

dom/webidl/MediaDevices.webidl

@@ -13,7 +13,7 @@
 [Func="Navigator::HasUserMediaSupport"]
 interface MediaDevices : EventTarget {
 //  attribute EventHandler ondevicechange;
-//  static Dictionary getSupportedConstraints (DOMString kind);
+  MediaTrackSupportedConstraints getSupportedConstraints();
 
   [Throws]
   Promise<sequence<MediaDeviceInfo>> enumerateDevices();

dom/webidl/MediaTrackSupportedConstraints.webidl

@@ -0,0 +1,35 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * http://dev.w3.org/2011/webrtc/editor/getusermedia.html
+ */
+
+dictionary MediaTrackSupportedConstraints {
+    boolean width = true;
+    boolean height = true;
+    boolean aspectRatio;        // to be supported
+    boolean frameRate = true;
+    boolean facingMode = true;
+    boolean volume;             // to be supported
+    boolean sampleRate;         // to be supported
+    boolean sampleSize;         // to be supported
+    boolean echoCancellation;   // to be supported
+    boolean latency;            // to be supported
+    boolean deviceId = true;
+    boolean groupId;            // to be supported
+
+    // Mozilla-specific extensions:
+
+    // http://fluffy.github.io/w3c-screen-share/#screen-based-video-constraints
+    // OBE by http://w3c.github.io/mediacapture-screen-share
+
+    boolean mediaSource = true;
+
+    // Experimental https://bugzilla.mozilla.org/show_bug.cgi?id=1131568#c3
+
+    boolean browserWindow = true;
+    boolean scrollWithPage = true;
+};

dom/webidl/moz.build

@@ -289,6 +289,7 @@ WEBIDL_FILES = [
     'MediaStreamError.webidl',
     'MediaStreamTrack.webidl',
     'MediaTrackConstraintSet.webidl',
+    'MediaTrackSupportedConstraints.webidl',
     'MenuBoxObject.webidl',
     'MessageChannel.webidl',
     'MessageEvent.webidl',