Revert "Revert 239763 "Add DiscardableMemoryAllocator to minimize use of...""

The previous attempt failed due to ASAN complaining during the
DiscardableMemory.TooLargeAllocationFails test (which is quite expected).

TBR=willchan
BUG=299828

Review URL: https://codereview.chromium.org/101953003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239816 0039d316-1c4b-4281-b951-d872f2087c98
Disable the avatar badge 'edit' function in metro Ash

We don't want the user to play with adding or editing
profiles in Ash until such time ash supports them.

BUG=325534

Review URL: https://codereview.chromium.org/103583004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239817 0039d316-1c4b-4281-b951-d872f2087c98
Revert 239426 "Create and use a seeded random number generator"

It was tickling a top-crasher.


> Create and use a seeded random number generator
> (PortSuggester) to suggest what ephemeral source port
> should be used when opening a UDP client socket in QUIC.
> 
> This should increase the likelihood of 0-RTT connections, even if a strike server is not used across a server cluster.
> 
> BUG=326545
> 
> Review URL: https://codereview.chromium.org/107803002

BUG=327057
TBR=jar@chromium.org

Review URL: https://codereview.chromium.org/102093003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239818 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239818