Validate enum parameters for IPCs in print_messages.h

This is part of a long-running background task to remove the remaining
uses of the unchecked IPC_ENUM_TRAITS() macro.

BUG=246708
R=vandebo@chromium.org

Review URL: https://codereview.chromium.org/145353018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248026 0039d316-1c4b-4281-b951-d872f2087c98
Let DTM filter out requested types that don't have controllers except for
control types.

BUG=339094

Review URL: https://codereview.chromium.org/140873003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248027 0039d316-1c4b-4281-b951-d872f2087c98
[invalidations] Created a stub about:invalidations

Added the minimum changes necessary to get the about:invalidations
page to display a "Works" text in HTML. In following patches,
functionality will be added to display the connection status,
the invalidations count for each datatype and other debugging
information.

Work was based on signin work carried out in issue=11377015 and
following patches.

BUG=263863

Review URL: https://codereview.chromium.org/144093005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248029 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248027
SVN changes up to revision 248029