Hooking MHTML generation to the browser.

This CL adds a class that can be used to generate MHTML for the current
page of a tab.
It is not yet surfaced in the UI.

BUG=None
TEST=Run the browser tests.


Review URL: http://codereview.chromium.org/7044095

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@89047 0039d316-1c4b-4281-b951-d872f2087c98
25 files changed