[Runtime] Use Manifest::HasPath() method instead of the
Manifest::HasKey().

Since the Manifest::HasKey() method is looking for the key under current
ValueDirectory object, this is not compatible with WGT manifest file
structure, so change it to Manifest::HasPath().

Fix one coding style issue.
[Tizen][Runtime] Add WGT csp handler unittest.

Add the unittest for WGT csp handler.

Fix a crash bug in WGT widget handler, which will cause the unittest
crash in some cases.
Merge pull request #1705 from takethathe/wgt_csp_handler

[Tizen][Runtime] Add the unittest for WGT CSP handler.