Remove ChromeViewMsg_AddStrictSecurityHost.

As of r221355, the renderer-side list of HSTS hosts it maintains is unused.

BUG=316632
TEST=compiles, no behavior change

Review URL: https://codereview.chromium.org/65473002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235872 0039d316-1c4b-4281-b951-d872f2087c98
When swapping web contents, destroy old native pages after the swap.

BUG=320168
TEST=Open a synced session and see it doesn't crash.

Review URL: https://codereview.chromium.org/66843016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235873 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235872
SVN changes up to revision 235873