Remove some unused stuff from basictypes.h.
Remove some unused stuff from basictypes.h.

My original goal was just to remove down_cast, since it uses RTTI, and I am
going to update the build with -fno-rtti.  The other stuff I just noticed is
unrelated and unused in our code, so we might as well remove it, since it
hasn't proven to be useful.

Review URL: http://codereview.chromium.org/63121


git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@13349 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser