Revert "Disk cache: Increase the maximum number of threads on the cache pool to 20."

reverts r239384

This reverts commit fefa1666597f12a7911caf93bf8983e83ba39c80.

> Disk cache: Increase the maximum number of threads on the cache pool to 20.
>
> Speculative fix to see if there's any perf change.
>
> BUG=325311
> TEST=none
> R=willchan@chromium.org
>
> Review URL: https://codereview.chromium.org/109363002

We did not see an improvement.

BUG=325311

Review URL: https://codereview.chromium.org/113873003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241207 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241207
DialServiceImpl now binds to all ipv4 and interfaces instead of just the first ipv4 found. Dedup is done using address family + interface index.
It now also checks if there are any other open sockets when notifying observers on error and sends a different error code (DIAL_SERVICE_NO_INTERFACES instead of the usual DIAL_SERVICE_SOCKET_ERROR) if there are no other open sockets. I need to confirm that the error codes are treated the same upstream currently. Later we should make sure DIAL_SERVICE_SOCKET_ERROR doesn't clear the device list.

Added unit tests for multiple interfaces and open sockets checking.

TEST=unit tests, did some manual testing at the lab.
BUG=300113

Review URL: https://codereview.chromium.org/113873004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241209 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241209