Revert 214325 "Revert 214254 "Add initial prototype for the GN m..."

The issue was already fixed :)

> Revert 214254 "Add initial prototype for the GN meta-buildsystem."
>
> It broke the check_licenses step on Android (see http://build.chromium.org/p/chromium.linux/builders/Android%20Builder%20%28dbg%29/builds/39904/steps/check_licenses/logs/stdio):
>
> @@@BUILD_STEP check_licenses@@@
> > /b/build/slave/Android_Builder__dbg_/build/src/android_webview/tools/webview_licenses.py scan
> Got LicenseError "missing README.chromium or licenses.py SPECIAL_CASES entry" while scanning tools/gn/secondary/base/third_party/dynamic_annotations
> Got LicenseError "missing README.chromium or licenses.py SPECIAL_CASES entry" while scanning tools/gn/secondary/third_party/modp_b64
> < /b/build/slave/Android_Builder__dbg_/build/src/android_webview/tools/webview_licenses.py scan
> ERROR: process exited with code 2
> @@@STEP_FAILURE@@@
>
>
> > Add initial prototype for the GN meta-buildsystem.
> >
> > This is currently not hooked into the build. To build, add a reference to the
> > gn.gyp file to build/all.gyp
> >
> > [email protected], [email protected]
> >
> > Review URL: https://codereview.chromium.org/21114002
>
> [email protected]
>
> Review URL: https://codereview.chromium.org/21084010

[email protected]

Review URL: https://codereview.chromium.org/21204003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@214333 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/.gn b/.gn
new file mode 100644
index 0000000..aaaf5e0
--- /dev/null
+++ b/.gn
@@ -0,0 +1,8 @@
+# This file is used by the experimental meta-buildsystem in src/tools/gn to
+# find the root of the source tree and to set startup options.
+
+# The location of the build configuration file.
+buildconfig = "//build/config/BUILDCONFIG.gn"
+
+# The secondary source root is a parallel directory tree where
+secondary_source = "//tools/gn/secondary/"