Update API for Objective-C RTCMediaConstraints.

BUG=

Review URL: https://codereview.webrtc.org/1543033003

Cr-Commit-Position: refs/heads/master@{#11172}
diff --git a/webrtc/api/api_tests.gyp b/webrtc/api/api_tests.gyp
index 466709c..c2c18bc 100644
--- a/webrtc/api/api_tests.gyp
+++ b/webrtc/api/api_tests.gyp
@@ -21,6 +21,7 @@
           'sources': [
             'objctests/RTCIceCandidateTest.mm',
             'objctests/RTCIceServerTest.mm',
+            'objctests/RTCMediaConstraintsTest.mm',
             'objctests/RTCSessionDescriptionTest.mm',
           ],
           'xcode_settings': {