To allow view-source of pages fully blocked by XSSAuditor, we need to
create a new back/forward entry for the blocked page instead of replacing
the current one (which is the normal behaviour implemented by the 
existing code).  This preserves the entry for the page which triggered the
block, and we can later base the view-source page on its contents.

We can't simply pass false to the existing code to get this behaviour, as 
other logic modifies this value and we don't get the desired result.

This is blocking the Chromium CL at https://codereview.chromium.org/304313003

Review URL: https://codereview.chromium.org/301163006

git-svn-id: svn://svn.chromium.org/blink/trunk@178194 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DataGrid: fix rendering glitch.

Because of different size calculation of DataGrid
header and body, some DataGrids are rendered with
glitch (see screenshot).

http://picpaste.com/eIbcgdKW.png

To fix this header is wrapped to div.
So it will be the same width as body.

BUG=

Review URL: https://codereview.chromium.org/394723002

git-svn-id: svn://svn.chromium.org/blink/trunk@178195 bbb929c8-8fbe-4397-9dbb-9b2b20218538