Implement ownProperty() and inheritFrom() assertions in should()

third_party/WebKit/LayoutTests/webaudio/unit-tests/audit.html

Index: third_party/WebKit/LayoutTests/webaudio/unit-tests/audit.html
diff --git a/third_party/WebKit/LayoutTests/webaudio/unit-tests/audit.html b/third_party/WebKit/LayoutTests/webaudio/unit-tests/audit.html
index 5c56e6a8b68a960e4ae38232f96ebda4b8a5c95b..a219d301159a2e44e14dbfcbab73a9d29b5d1db8 100644
--- a/third_party/WebKit/LayoutTests/webaudio/unit-tests/audit.html
+++ b/third_party/WebKit/LayoutTests/webaudio/unit-tests/audit.html
@@ -36,6 +36,18 @@
         should(should(1).beEqualTo(1), 'should(1).beEqualTo(1)').beTrue();
         should(true, 'The message is').message('truthful!', 'false!');
 
+        should(BaseAudioContext.prototype, 'BaseAudioContext.prototype')
+            .haveOwnProperty('createGain');
+        should(BaseAudioContext.prototype, 'BaseAudioContext.prototype')
+            .notHaveOwnProperty('startRendering');
+
+        let ac = new AudioContext();
+        let sourceNode = new AudioBufferSourceNode(ac);
+        should(sourceNode, 'An AudioBufferSourceNode')
+            .inheritFrom('AudioScheduledSourceNode');
+        should(sourceNode, 'An AudioBufferSourceNode')
+            .inheritFrom('AudioNode');
+
         let oac = new OfflineAudioContext(1, 128, 44100);
         Promise.all([
             should(oac.startRendering(), 'Start OAC rendering').beResolved(),