add gflags to deps to allow command line parameters.

DEPS

 vars = {
   # Override root_dir in your .gclient's custom_vars to specify a custom root
   # folder name.
   "root_dir": "libyuv",
   "extra_gyp_flag": "-Dextra_gyp_flag=0",
 
   # Roll the Chromium Git hash to pick up newer versions of all the
   # dependencies and tools linked to in setup_links.py.
   '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.
     "name": "sync chromium",
     "pattern": ".",
     "action": ["python", "-u", Var("root_dir") + "/sync_chromium.py",
                "--target-revision", Var("chromium_revision")],
   },
   {
     # Create links to shared dependencies in Chromium.
     "name": "setup_links",
     "pattern": ".",
     "action": ["python", Var("root_dir") + "/setup_links.py"],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
     "action": ["python", Var("root_dir") + "/gyp_libyuv"],
   },
 ]