Introduce 'chromium-efl-libs.spec'.

Introduce 'chromium-efl-libs.spec'.

Goal of the patch is:
build and pack all chromium targets that both 'xwalk'
and 'chromium-ewk' targets depends on, using a component build.
Note that any target define in xwalk/ or tizen_src/ewk/
directories are excluded.
As result, chromium-efl-libs.rpm will contain all .so files
that xwalk and chromium-ewk targets requires to get build.

In a follow up patch, a crosswalk-bin.spec will be
introduced, and it will depend on chromium-efl-libs.rpm.
crosswalk-bin will build all xwalk targets, but not the chromium
targets already built by chromium-efl-libs.
This will speed up xwalk development cycle.

* packaging/chromium-efl-libs.spec: fork of the xwalk's crosswalk-libs.spec.
  Difference from the original: It adds some dependencies needed by
  chromium-efl sources; it also, calls gyp_chromiumefl.sh instead of
  directly calling gyp_xwalk.

* packaging/print-chromium-deps.py: fork of the xwalk version.
  Difference from the original: it changes the if condition that
  filter out xwalki and chromium-ewk targets from the final output.
  Script processes dump.json, which is the output of GYP when
  "dump_dependency_json" is set to GYP_GENERATORS.
  It prints out a list of targets to be built.

* packaging/chromium-efl-libs.manifest: copy from xwalk.

The change in system.gyp is needed because on component
builds, target that 'base' depends on directly need to
have a toolsets definition. see [1] for reference.

[1] http://codereview.chromium.org/7904034

How to use use:
$ tizen_src/build/build_mobile.sh --libs

Bug: http://107.108.218.239/bugzilla/show_bug.cgi?id=13316
Reviewed by: Hyunhak Kim, arno renevier

Change-Id: I3268bc7aaff5bfa3ffda24c41da048654dbec75e
Signed-off-by: Antonio Gomes <a1.gomes@samsung.com>