Add temporary instrumentation to diagnose a RenderTextWin crash.

See investigation notes from the bug and the comment in this CL.

BUG=348103

Review URL: https://codereview.chromium.org/184903002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254253 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254253