Fix D-pad navigation between URI bar and Webview.

Fix D-pad navigation between URI bar and Webview.

[Issue]    https://bugs.tizen.org/jira/browse/TT-211
[Problem]  Navigation on webview elements is not possible because
           focus go to URI bar when UP is pressed.
[Cause]    No webview focus lock implemented.
[Solution] Implement focus auto lock on webview.
[Verify]   Load sample page, go by D-pad to webview, navigate on webview
           elements, to back to URI bar press RED button [F4 on keyboard].

Change-Id: Ia24378ac090364e43b85fba89f5fd3a42f48cc26
Signed-off-by: Dariusz Frankiewicz <d.frankiewic@samsung.com>