Revert 161545 "Align HTMLAppletElement IDL with spec"

Possible cause of ExtensionHostFactoryTest.IncognitoExtensionHosts crash.

> Align HTMLAppletElement IDL with spec
> 
> http://whatwg.org/html#htmlappletelement
> 
> In addition to removing TreatNullAs=NullString, align with the spec by
> making hspace/vspace unsigned long, and codebase/object URLs.
> 
> The tests for the updated properties pass in Firefox Nightly, IE11
> Release Preview and Opera 12.16, with these exceptions:
> 
> IE11 returns "" after setting width/height to null and fails all of
> the vspace/hspace reflection tests in ways not per spec.
> 
> Presto doesn't reflect object as a URL, but the framework didn't
> notice that before the minor fix in nullTestElementAttribute.
> Presto also fails the vspace/hspace set tests in ways not per spec.
> 
> BUG=316129, 310298
> 
> Review URL: https://codereview.chromium.org/64173002

BUG=316334
TBR=philipj@opera.com

Review URL: https://codereview.chromium.org/65323002

git-svn-id: svn://svn.chromium.org/blink/trunk@161556 bbb929c8-8fbe-4397-9dbb-9b2b20218538