[EFL][WK2] Add ewk_view_page_contents_get() API
https://bugs.webkit.org/show_bug.cgi?id=106440

Patch by KwangYong Choi <ky0.choi@samsung.com> on 2013-01-11
Reviewed by Gyuyoung Kim.

Add ewk_view_page_contents_get() API for getting contents of the current page.
Currently, it supports only MHTML type.

* UIProcess/API/efl/ewk_view.cpp:
(Ewk_Page_Contents_Context):
(ewkViewPageContentsCallback):
(ewk_view_page_contents_get):
* UIProcess/API/efl/ewk_view.h:
* UIProcess/API/efl/tests/test_ewk2_view.cpp:
(PageContentsCallback):
(TEST_F):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@139422 268f45cc-cd09-0410-ab3c-d52691b4dbfc