gyp_xwalk: Reduce delta with gyp_chromium.py.
gyp_xwalk: Reduce delta with gyp_chromium.py.

Sync with the upstream version of this file. This time there are not
many changes, other than the fact that the code upstream moved from
gyp_chromium to gyp_chromium.py.

List of relevant commits:
d9aaae0 Add 'build' directory to import path of gyp_chromium.
1eeaa32 Move logic of gyp_chromium into gyp_chromium.py

baleboy/crosswalk,rakuco/crosswalk,hgl888/crosswalk,baleboy/crosswalk,heke123/crosswalk,rakuco/crosswalk,marcuspridham/crosswalk,hgl888/crosswalk,PeterWangIntel/crosswalk,marcuspridham/crosswalk,baleboy/crosswalk,xzhan96/crosswalk,crosswalk-project/crosswalk,rakuco/crosswalk,dreamsxin/crosswalk,axinging/crosswalk,xzhan96/crosswalk,lincsoon/crosswalk,lincsoon/crosswalk,lincsoon/crosswalk,xzhan96/crosswalk,darktears/crosswalk,PeterWangIntel/crosswalk,hgl888/crosswalk,crosswalk-project/crosswalk,rakuco/crosswalk,dreamsxin/crosswalk,PeterWangIntel/crosswalk,heke123/crosswalk,crosswalk-project/crosswalk,axinging/crosswalk,marcuspridham/crosswalk,heke123/crosswalk,baleboy/crosswalk,lincsoon/crosswalk,xzhan96/crosswalk,darktears/crosswalk,dreamsxin/crosswalk,crosswalk-project/crosswalk,dreamsxin/crosswalk,xzhan96/crosswalk,xzhan96/crosswalk,marcuspridham/crosswalk,darktears/crosswalk,darktears/crosswalk,crosswalk-project/crosswalk,axinging/crosswalk,axinging/crosswalk,rakuco/crosswalk,xzhan96/crosswalk,heke123/crosswalk,rakuco/crosswalk,marcuspridham/crosswalk,darktears/crosswalk,heke123/crosswalk,axinging/crosswalk,baleboy/crosswalk,dreamsxin/crosswalk,hgl888/crosswalk,dreamsxin/crosswalk,lincsoon/crosswalk,PeterWangIntel/crosswalk,axinging/crosswalk,hgl888/crosswalk,baleboy/crosswalk,crosswalk-project/crosswalk,darktears/crosswalk,heke123/crosswalk,crosswalk-project/crosswalk,xzhan96/crosswalk,hgl888/crosswalk,dreamsxin/crosswalk,PeterWangIntel/crosswalk,heke123/crosswalk,PeterWangIntel/crosswalk,hgl888/crosswalk,baleboy/crosswalk,lincsoon/crosswalk,marcuspridham/crosswalk,marcuspridham/crosswalk,darktears/crosswalk,rakuco/crosswalk,rakuco/crosswalk,crosswalk-project/crosswalk,heke123/crosswalk,axinging/crosswalk,lincsoon/crosswalk,PeterWangIntel/crosswalk,marcuspridham/crosswalk,baleboy/crosswalk,darktears/crosswalk,hgl888/crosswalk,lincsoon/crosswalk