When right clicking in a text area that is scrolled, the wrong word is selected.  This is because we use the wrong node when getting the selection.  We want to use the shadow inner node, but the hit test result provided to the ContextMenu is not the shadow node.  To work around this, we recompute the hit test result.
When right clicking in a text area that is scrolled, the wrong
word is selected.  This is because we use the wrong node when
getting the selection.  We want to use the shadow inner node,
but the hit test result provided to the ContextMenu is not
the shadow node.  To work around this, we recompute the
hit test result.

BUG=613
TEST=Go to a page with a text area, add text until a scroll bar
  appears, scroll the text area and right click on a word.  The
  word under the cursor should be highlighted.

Review URL: http://codereview.chromium.org/8853

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@4118 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