Integrate chromedriver in a simpler way.

Integrate chromedriver in a simpler way.

In patches [1] and [2], chromedriver was originally
integrated to chromium-efl by forking chrome/chrome_tests.gypi
and making the needed changes: ewk/efl_integration/chromedriver_efl.gypi.

After studying chromedriver build, it was found out that
chrome/chrome.gyp is its main entry point.
Given that chrome.gyp does far more than only warm-up
chromedriver builds, it is not feasible to simply
including it from chromium-efl side.

This patch relies on the s-chromium patch [3] in order to
simplify our chromedriver integration. Now, chromedriver_efl.gypi
(our fork) can be deleted, and we can simply build
'chromedriver' target, instead of 'chromedriver_efl'
Also, we can refer to 'chromedriver' everywhere instead
of 'chromedriver_efl'.

[1] http://165.213.202.130/gerrit/#/c/83743
[2] http://165.213.202.130/gerrit/#/c/83742
[3] http://165.213.202.130/gerrit/#/c/95036

Original beta/m42 patch:
- http://165.213.202.130/gerrit/#/c/85836/ reviewed by
Janusz Majnert, SeungSeop Park.

Together with: Id66b0fe16d6f94c7698dc056f3f1f71f4e536e5f

Bug: http://web.sec.samsung.net/bugzilla/show_bug.cgi?id=14773

Reviewed by: a.renevier, a1.gomes, sns.park

Change-Id: I314e3853fb740848102026cbdeaa6881242ac8c0
Signed-off-by: Antonio Gomes <a1.gomes@samsung.com>