Validate finiteness of HTMLMediaElement properties.

LayoutTests/media/video-playbackrate.html

Index: LayoutTests/media/video-playbackrate.html
diff --git a/LayoutTests/media/video-playbackrate.html b/LayoutTests/media/video-playbackrate.html
index 0ef2fc7ec897216e2d974269a49cedeceffcb57a..453e5d46fcbc517172f223be250867b4fe4a8005 100644
--- a/LayoutTests/media/video-playbackrate.html
+++ b/LayoutTests/media/video-playbackrate.html
@@ -79,6 +79,18 @@
                 run("video.playbackRate = Number.MAX_VALUE");
                 testExpected("video.playbackRate", Number.MAX_VALUE);
                 consoleWrite("");
+
+                consoleWrite("Test non-finite playback rates");
+                testException("video.defaultPlaybackRate = -Infinity", "TypeError: Failed to set the 'defaultPlaybackRate' property on 'HTMLMediaElement': The value provided is infinite.");
+                testException("video.defaultPlaybackRate = Infinity", "TypeError: Failed to set the 'defaultPlaybackRate' property on 'HTMLMediaElement': The value provided is infinite.");
+                testException("video.defaultPlaybackRate = NaN", "TypeError: Failed to set the 'defaultPlaybackRate' property on 'HTMLMediaElement': The value provided is not a number.");
+                consoleWrite("");
+
+                testException("video.playbackRate = -Infinity", "TypeError: Failed to set the 'playbackRate' property on 'HTMLMediaElement': The value provided is infinite.");
+                testException("video.playbackRate = Infinity", "TypeError: Failed to set the 'playbackRate' property on 'HTMLMediaElement': The value provided is infinite.");
+                testException("video.playbackRate = NaN", "TypeError: Failed to set the 'playbackRate' property on 'HTMLMediaElement': The value provided is not a number.");
+                consoleWrite("");
+
                 endTest();
             }