Move clipboard_utils.* from webkit/renderer to content/renderer.

compositor_bindings/ will be moved separately since it is its own beast.

cpp_* will also be moved later.

BUG=265753
TEST=None, just moving files around. :/
R=jamesr@chromium.org,avi@chromium.org,jochen@chromium.org

Review URL: https://codereview.chromium.org/25378002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226477 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226477