popup picker should be memeber of webview instance.

popup picker should be memeber of webview instance.

[Title] popup picker should be memeber of webview instance.
[Issue#] P130912-04605
[Problem] open the popup picker by clicking select tag, and home -> click the shortcut to navigate any sites.
          Then, popup picker was remained although new sites are shown.
[Cause] picker was member of webview instance but it remains although webview was hidden.
[Solution] Make picker as member of webview instance.
           So webview became hidden, picker will be hidden.

Change-Id: Iffe21159ab53768176c2e8a0dc4b3ada7b3ad0bc