Save page class changes (such as addition of bloom-trilingual)

I don't think it's necessary to remove them; in fact it's useful to verify that the setup code works...I think what's bothering me is the difficulty of understanding the structure of the test. A good unit test should have a distinction between setting things up (and perhaps checking something about setup), exercising the system being tested, and verifying the results. This is aggravated (I find) by the ease of overlooking the distinction between 0 and 1 as the last argument of AssertThatXmlIn(). In this case it's not very clear whether we're primarily testing the behavior of GetEditiableHtmlDomForPage or SavePage. A comment clarifying this would help.

I also still find it surprising that UpdateContentLanguageClasses adds a trilingual class by default...I would have expected that to only happen if something explicitly configures a trilingual book. A comment about that might also be helpful.