Allow policy refresh rate to be configured through policy.

chrome/browser/policy/device_token_fetcher.cc

Index: chrome/browser/policy/device_token_fetcher.cc
diff --git a/chrome/browser/policy/device_token_fetcher.cc b/chrome/browser/policy/device_token_fetcher.cc
index 2d514b603aae312e454ad2f1e5247e9f01e418c7..3f977c1a25ccfdbc754e1f8d841cda5ccd9bb9fc 100644
--- a/chrome/browser/policy/device_token_fetcher.cc
+++ b/chrome/browser/policy/device_token_fetcher.cc
@@ -65,6 +65,7 @@ DeviceTokenFetcher::ObserverRegistrar::~ObserverRegistrar() {
 
 void DeviceTokenFetcher::ObserverRegistrar::Init(
     DeviceTokenFetcher* token_fetcher) {
+  RemoveAll();
   token_fetcher_ = token_fetcher;
 }
 
@@ -192,7 +193,11 @@ void DeviceTokenFetcher::OnError(DeviceManagementBackend::ErrorCode code) {
 }
 
 void DeviceTokenFetcher::Restart() {
-  DCHECK(!IsTokenPending());
+  // Complain if there's currently an asynchronous operation going on.
+  DCHECK(state_ == kStateNotStarted ||
+         state_ == kStateHasDeviceToken ||
+         state_ == kStateFailure ||
+         state_ == kStateNotManaged);
   device_token_.clear();
   device_token_load_complete_event_.Reset();
   MakeReadyToRequestDeviceToken();