Implement the DisplayMediaStreamOptions monitorTypeSurfaces

This adds the ability for web applications to provide a hint, indicating
to the user agent whether the application, upon calling getDisplayMedia,
wishes the user has the option to choose the display surfaces whose type
is monitor (screen).

Spec PR: w3c/mediacapture-screen-share#274
Spec: https://w3c.github.io/mediacapture-screen-share/#dom-displaymediastreamoptions-monitortypesurfaces
Intent to ship: TODO
Demo: https://screen-sharing-controls.glitch.me/?monitorTypeSurfaces=exclude
Bug: 1477706
Change-Id: I25ffabe546ddc778f660834e44a9dab15494e92a

screen-capture/getdisplaymedia.https.html

@@ -192,6 +192,25 @@
     }, `getDisplayMedia({"video":{"displaySurface":"${displaySurface}"}}) with getSettings`);
   })
 }
+promise_test(async (t) => {
+  const stream = await getDisplayMedia({
+    video: { displaySurface: "monitor" },
+    monitorTypeSurfaces: "include",
+  });
+  t.add_cleanup(() => stopTracks(stream));
+  const { displaySurface } = stream.getTracks()[0].getSettings();
+  assert_equals(displaySurface, "monitor");
+}, `getDisplayMedia({"video":{"displaySurface":"monitor"},"monitorTypeSurfaces":"include"}) resolves with a monitor track`);
+
+promise_test(async (t) => {
+  const stream = await getDisplayMedia({
+    video: { displaySurface: "monitor" },
+    monitorTypeSurfaces: "exclude",
+  });
+  t.add_cleanup(() => stopTracks(stream));
+  const { displaySurface } = stream.getTracks()[0].getSettings();
+  assert_any(assert_equals, displaySurface, ["window", "browser"]);
+}, `getDisplayMedia({"video":{"displaySurface":"monitor"},"monitorTypeSurfaces":"exclude"}) resolves with a non monitor track`);
 
 {
   const properties = ["displaySurface"];