SPDY - persist 300 most recently used servers that support SPDY to preferences file

SPDY - persist 300 most recently used  servers that support SPDY to
preferences file.

This change reduces the size of Preferences file for around 3% of users
who have lot of entries (some users have more than 10,000 entries).

HttpServerProperties - Implement MRU for supports SPDY server list.
Persist only the most recently used 300 entries. In memory keep all the
entries.

This change is similar to MRU change for AlternateProtocol.

R=rch@chromium.org, mmenke@chromium.org
BUG=258189
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=267022

[Ryan Hamilton, 2014-04-29 18:13:37]

lgtm

[ramant (doing other things), 2014-04-29 18:26:59]

Hi Matt,
  Could you please review content/browser/loader, chrome/browser/net changes for
OWNERS approval? 

  It is surprising rch is not in OWNERS list for chrome/browser/net.

thanks very much
raman

[mmenke, 2014-04-29 19:28:37]

On 2014/04/29 18:26:59, ramant wrote:
> Hi Matt,
>   Could you please review content/browser/loader, chrome/browser/net changes
for
> OWNERS approval? 
> 
>   It is surprising rch is not in OWNERS list for chrome/browser/net.
> 
> thanks very much
> raman

content/browser/loader and chrome/browser/net LGTM.  I certainly have no
objections to expanding the ownership for chrome/browser/net.

[ramant (doing other things), 2014-04-29 19:30:41]

On 2014/04/29 19:28:37, mmenke wrote:
> On 2014/04/29 18:26:59, ramant wrote:
> > Hi Matt,
> >   Could you please review content/browser/loader, chrome/browser/net changes
> for
> > OWNERS approval? 
> > 
> >   It is surprising rch is not in OWNERS list for chrome/browser/net.
> > 
> > thanks very much
> > raman
> 
> content/browser/loader and chrome/browser/net LGTM.  I certainly have no
> objections to expanding the ownership for chrome/browser/net.

thanks much mmenke

[ramant (doing other things), 2014-04-29 19:30:46]

The CQ bit was checked by rtenneti@chromium.org

[commit-bot: I haz the power, 2014-04-29 19:32:50]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rtenneti@chromium.org/253903002/120001

[commit-bot: I haz the power, 2014-04-30 01:11:38]

Change committed as 267022