Do not call moveCaretSelectionTowardsWindowPoint() (deprecated).

Instead just call moveCaretSelection() which seems to be the
recommended, non-deprecated version.

BUG=None
TEST=content_unittests --gtest_filter=RenderViewImplTest.*
R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/84523002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237476 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237476