Refactoring WidgetView for apply cornerRadius in WidgetView

Refactoring WidgetView for apply cornerRadius in WidgetView

This patch fetches WidgetView CornerRadius-related functionality from Tizen 7.0 to Tizen 10.0.
with this patch, the CornerRadius feature is available for both WidgetView and preview images.

the details of the patch are as follows.
- Apply CornerRadius to WidgetView(483a8569571b9de8f7cf46d8de5889d130ff0d01)
- Fix bug after applying cornerRadius(91f97edb70043fea02b2301f665d832c96c9bccd)
- Fix svace issue in cornerRadius(4bfb1eba63aa4b93985ad8bab21b450b0a2d1f76)
- Enable premultiply using CornerRadius (5f58a6e30525857212b7d7b29450c05f37a26e7e)
- Apply cornerRadius in preview(b83423334bf3fdbced594b5cd6703db12fb59c70)
- Call widget_instance_resize() only when the size is changed(ec308f28f466b1de1c19af907b158cfe79b39086)

Change-Id: I37249bfa598e78a26497af68ff1bd5de03f73863