[Gtk] Fix gtk_floating_container_forall ordering.

Floating children are placed above the single child from GtkBin, so
we should visit them first. This fixes:
- overlay devtools no longer block drag events in page;
- user can drag and drop from the page to find bar.

BUG=329539

Review URL: https://codereview.chromium.org/98013004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241697 0039d316-1c4b-4281-b951-d872f2087c98
Run all flag-checks for new-profile-managment et al through common functions for future Finch integration.

In order to do tests and a safe, controlled roll-out of Chrome's new profile management, we're going to enable it using a Finch experiment.  The current tests of the existing command-line flags all need to be routed through common functions in order to override these settings if a Finch experiment is set.

Affected flags are:
  --new-profile-management
  --enable-inline-signin
  --google-profile-info

Note that there existed a function to test for NewProfileManagement but it was not in a good place for general testing and definitely not for other flags so it has been extracted as well.

BUG=324046

Review URL: https://codereview.chromium.org/108803007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241698 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241697
[MemSheriff] Widen suppression

BUG=106912
TBR=thestig@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/116433005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241699 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241699