Revert 44049 - Enable blank document checks in dom checker.
Revert 44049 - Enable blank document checks in dom checker.

Broke dom_checker_tests on Chromium Linux and Chromium Linux x64.

BUG=9394
Test=DomCheckerTest
Review URL: http://codereview.chromium.org/1609015

TBR=inferno@chromium.org
Review URL: http://codereview.chromium.org/1627013

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@44053 0039d316-1c4b-4281-b951-d872f2087c98

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