Fix gn gen for iOS.

BUG=459705

Review URL: https://codereview.chromium.org/1267583003

Cr-Original-Commit-Position: refs/heads/master@{#341530}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 53f0f1ac021043f7aba990be4a44de21e18eebe8

config/features.gni

@@ -60,7 +60,8 @@ declare_args() {
   # TODO(GYP) The GYP build has || chromecast==1 for this:
   proprietary_codecs = is_android || is_chrome_branded
 
-  enable_configuration_policy = true
+  # TODO(gyp) true
+  enable_configuration_policy = !is_ios
 
   # Enables support for background apps.
   enable_background = !is_ios && !is_android