GN: Implement BUILD.gn for common_video.
This adds copying of Chromium's third_party/BUILD.gn
to acommondate libyuv's BUILD.gn that imports the 'jpeg'
config from that file.
BUG=3441
TEST=trybots + local compile passing with:
gn gen out/Default --args="build_with_chromium=false" && ninja -C out/Default
gn gen out/Default --args="build_with_chromium=false build_libyuv=false" && ninja -C out/Default
R=niklas.enbom@webrtc.org, pbos@webrtc.org
Review URL: https://webrtc-codereview.appspot.com/14839004
git-svn-id: http://webrtc.googlecode.com/svn/trunk@6595 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/.gitignore b/.gitignore
index 911aade..57808e3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -55,6 +55,8 @@
/third_party/android_tools
/third_party/asan
/third_party/binutils
+/third_party/build_gn
+/third_party/BUILD.gn
/third_party/clang_format
/third_party/colorama
/third_party/cygwin