Fix MediaSource.duration setter behavior to match the current spec.

LayoutTests/http/tests/media/media-source/mediasource-remove.html

Index: LayoutTests/http/tests/media/media-source/mediasource-remove.html
diff --git a/LayoutTests/http/tests/media/media-source/mediasource-remove.html b/LayoutTests/http/tests/media/media-source/mediasource-remove.html
index 4306546cbee0e2889b9a7e557b135812cfe933bc..f6df6edbd5632130fefab10aa5fac1983c3dfbc1 100644
--- a/LayoutTests/http/tests/media/media-source/mediasource-remove.html
+++ b/LayoutTests/http/tests/media/media-source/mediasource-remove.html
@@ -129,6 +129,34 @@
               });
           }, "Test aborting a remove operation.");
 
+          mediasource_testafterdataloaded(function(test, mediaElement, mediaSource, segmentInfo, sourceBuffer, mediaData)
+          {
+              sourceBuffer.appendBuffer(mediaData);
+
+              test.expectEvent(sourceBuffer, "updatestart");
+              test.expectEvent(sourceBuffer, "update");
+              test.expectEvent(sourceBuffer, "updateend");
+
+              test.waitForExpectedEvents(function()
+              {
+                  mediaSource.duration = 10;

[philipj_slow, 2014/06/16 13:26:19]

Can you assert_less_than(mediaSource.duration, 10) before this? It explains why
updating is still false afterwards, which I didn't understand at first.

[acolwell GONE FROM CHROMIUM, 2014/06/17 01:24:02]

Done.

+
+              assert_false(sourceBuffer.updating, "updating");

[philipj_slow, 2014/06/16 13:26:18]

nit: misindented from here

[acolwell GONE FROM CHROMIUM, 2014/06/17 01:24:02]

Done.

+
+              sourceBuffer.remove(mediaSource.duration, mediaSource.duration + 2);
+
+              assert_true(sourceBuffer.updating, "updating");
+              test.expectEvent(sourceBuffer, "updatestart");
+              test.expectEvent(sourceBuffer, "update");
+              test.expectEvent(sourceBuffer, "updateend");
+              });
+
+              test.waitForExpectedEvents(function()
+              {
+                  test.done();
+              });
+
+          }, "Test remove with a start at the duration.");
 
           mediasource_testafterdataloaded(function(test, mediaElement, mediaSource, segmentInfo, sourceBuffer, mediaData)
           {