[MM] Remove duplicated enums from MM codes.

[MM] Remove duplicated enums from MM codes.

This patch is to remove duplicated NetworkState and ReadyState
from codes and use already-existing blink::WebMediaPlayer::NetworkState
and blink::WebMediaPlayer::ReadyState.

Bug: http://168.219.209.56/jira/browse/TSAM-536
Reference: http://suprem.sec.samsung.net/gerrit/#/c/54032
Reference: http://suprem.sec.samsung.net/gerrit/#/c/56307

Reviewed by: sm.venugopal, sns.park

Change-Id: Ic81fb513f41d1e7d9a688b66f798cd3f827b47ea
Signed-off-by: msu.koo <msu.koo@samsung.com>