Add Chromoting curtain-mode policy.

remoting/host/policy_hack/policy_watcher.cc

Index: remoting/host/policy_hack/policy_watcher.cc
diff --git a/remoting/host/policy_hack/policy_watcher.cc b/remoting/host/policy_hack/policy_watcher.cc
index 0d197729c4784f350473e31dc704fc18d64bd39b..4217076b04e6eea189aeb0905db8dbaf4dd759c2 100644
--- a/remoting/host/policy_hack/policy_watcher.cc
+++ b/remoting/host/policy_hack/policy_watcher.cc
@@ -97,6 +97,9 @@ scoped_ptr<base::DictionaryValue> AddDefaultValuesWhenNecessary(
   CopyStringOrDefault(to.get(), from,
                       PolicyWatcher::kHostTalkGadgetPrefixPolicyName,
                       kDefaultTalkGadgetPrefix, kDefaultTalkGadgetPrefix);
+  CopyBooleanOrDefault(to.get(), from,
+                       PolicyWatcher::kHostRequireCurtainPolicyName,
+                       false, false);
 
   return to.Pass();
 }
@@ -115,6 +118,9 @@ const char PolicyWatcher::kHostDomainPolicyName[] =
 const char PolicyWatcher::kHostTalkGadgetPrefixPolicyName[] =
     "RemoteAccessHostTalkGadgetPrefix";
 
+const char PolicyWatcher::kHostRequireCurtainPolicyName[] =
+    "RemoteAccessHostRequireCurtain";
+
 const char* const PolicyWatcher::kBooleanPolicyNames[] =
     { PolicyWatcher::kNatPolicyName,
       PolicyWatcher::kHostRequireTwoFactorPolicyName