add gflags to deps to allow command line parameters.

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index b621246292cdd6b3db7117c56cea45d7fb3bfabe..b9451276bc7049f95842e668a365c75b30cdfb4e 100644
--- a/DEPS
+++ b/DEPS
@@ -9,6 +9,16 @@ vars = {
   'chromium_revision': 'bb79186c63ff4eff7a2a318a21731005c53f269b',
 }
 
+# NOTE: Prefer revision numbers to tags for svn deps. Use http rather than
+# https; the latter can cause problems for users behind proxies.
+deps = {
+  'src/third_party/gflags/src':
+    Var('chromium_git') + '/external/gflags/src@e7390f9185c75f8d902c05ed7d20bb94eb914d0c', # from svn revision 82
+}
+
+# Define rules for which include paths are allowed in our source.
+include_rules = [ '+gflags' ]
+
 hooks = [
   {
     # Clone chromium and its deps.