linux_aura: Fix PRIMARY selection in the content area.

When selecting any text in the content area, we put the entire text
range on the PRIMARY clipboard instead of just the selected text. This
patch copies what RWHVGtk does to RWHVAura.

BUG=341105
R=ben@chromium.org

Review URL: https://codereview.chromium.org/205493003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@258336 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed