Introduce GN config files.

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index 03c879a2970b29ccccdfcacab0b4fca3b2e1e353..7f4cef692fc3b4ff3a3a857fae4fe4f7a3cd1ded 100644
--- a/DEPS
+++ b/DEPS
@@ -20,11 +20,15 @@ vars = {
 
   "chromium_git": "https://chromium.googlesource.com",
   "buildtools_revision": "a7cc7a3e21a061975b33dcdcd81a9716ba614c3c",
+  "icu_revision": "9cd2828740572ba6f694b9365236a8356fd06147",
 }
 
 deps = {
   Var("root") + "/buildtools":
-    Var('chromium_git') + '/chromium/buildtools.git' + '@' +  Var('buildtools_revision'),
+    (Var('chromium_git') + '/chromium/buildtools.git' + '@' +
+     Var('buildtools_revision')),
+  Var("root") + "/third_party/icu":
+    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + Var('icu_revision'),
 }
 
 include_rules = [
@@ -63,6 +67,12 @@ hooks = [
   },
   # TODO(veranika): run GN here.
   {
+    "name": "lastchange",
+    "pattern": ".",
+    "action": ["python", "src/build/util/lastchange.py",
+               "-o", "src/build/util/LASTCHANGE"],
+  },
+  {
     "name": "download_clang_format",
     "pattern": ".",
     "action": ["download_from_google_storage",