Update WebRtcGetUserMediaBrowserTest.ApplyConstraintsVideoTwoStreams

Use exact constraints and explicit values in order to reduce the
probability of flakes.

Bug: 1055012
Change-Id: I5b232694710c90682c9e143895af9979a400d858
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2336076Reviewed-by: Marina Ciocea <marinaciocea@chromium.org>
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794989}

content/test/data/media/getusermedia.html

@@ -689,39 +689,41 @@
   }
 
   function applyConstraintsVideoTwoStreams() {
-    navigator.mediaDevices.getUserMedia({video:true})
-      .then(stream => {
+    navigator.mediaDevices.getUserMedia({
+        video:{
+            width:{exact:640},
+            height: {exact:480}
+        }
+    }).then(stream => {
         assertEquals(stream.getVideoTracks().length, 1);
-        var track1 = stream.getVideoTracks()[0];
+        let track1 = stream.getVideoTracks()[0];
+        let deviceId1 = track1.getSettings().deviceId;
         track1.onmute = () => failTest("Unexpected mute of track1");
         track1.onunmute = () => failTest("Unexpected unmute of track1");
-        var settings1 = track1.getSettings();
-        var default_device_id = settings1.deviceId;
-        var default_width = settings1.width;
-        var default_height = settings1.height;
-        return navigator.mediaDevices.getUserMedia({video:true})
-          .then(stream2 => {
-            var track2 = stream2.getVideoTracks()[0];
+        return navigator.mediaDevices.getUserMedia({
+            video:{
+                deviceId: {exact: deviceId1},
+                width:{exact:640},
+                height: {exact:480}
+            }
+        }).then(stream2 => {
+            let track2 = stream2.getVideoTracks()[0];
             track2.onmute = () => failTest("Unexpected mute of track2");
             track2.onunmute = () => failTest("Unexpected unmute of track2");
-            var settings2 = track2.getSettings();
-            assertEquals(settings2.width, default_width);
-            assertEquals(settings2.height, default_height);
-            assertEquals(settings2.deviceId, default_device_id);
             return track1.applyConstraints({
-              width: default_width-1,
-              height: default_height-1
+              width: {exact: 639},
+              height: {exact: 479}
             }).then(()=> {
               assertEquals(track1.readyState, "live");
-              settings1 = track1.getSettings();
-              assertEquals(settings1.deviceId, default_device_id);
-              assertEquals(settings1.width, default_width - 1);
-              assertEquals(settings1.height, default_height - 1);
+              let settings1 = track1.getSettings();
+              assertEquals(639, settings1.width);
+              assertEquals(479, settings1.height);
               assertEquals(track2.readyState, "live");
-              settings2 = track2.getSettings();
-              assertEquals(settings2.deviceId, default_device_id);
-              assertEquals(settings2.width, default_width);
-              assertEquals(settings2.height, default_height);
+              let settings2 = track2.getSettings();
+              assertEquals(640, settings2.width);
+              assertEquals(480, settings2.height);
+              assertEquals(deviceId1, settings1.deviceId);
+              assertEquals(deviceId1, settings2.deviceId);
               track1.stop();
               track2.stop();
               reportTestSuccess();