[Origin Trials] Support updates of disabled token list

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index a6244ebc002cf72a0c388d006ced5fe21bdc4db8..e116f38071c21d8f26836ef15f0a038b382f4e6b 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -2390,6 +2390,9 @@ const char kOriginTrialPublicKey[] = "origin_trials.public_key";
 // A list of origin trial features to disable by policy.
 const char kOriginTrialDisabledFeatures[] = "origin_trials.disabled_features";
 
+// A list of origin trial tokens to disable by policy.
+const char kOriginTrialDisabledTokens[] = "origin_trials.disabled_tokens";
+
 // Policy that indicates the state of updates for the binary components.
 const char kComponentUpdatesEnabled[] =
     "component_updates.component_updates_enabled";