📰 The Status card reports disabled sync states

components/ntp_snippets/ntp_snippets_status_service.cc

Index: components/ntp_snippets/ntp_snippets_status_service.cc
diff --git a/components/ntp_snippets/ntp_snippets_status_service.cc b/components/ntp_snippets/ntp_snippets_status_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..61802cd9737308e7fa89980c3618c5cbdf869324
--- /dev/null
+++ b/components/ntp_snippets/ntp_snippets_status_service.cc
@@ -0,0 +1,86 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/ntp_snippets/ntp_snippets_status_service.h"
+#include "components/signin/core/browser/signin_manager.h"
+#include "components/sync_driver/sync_service.h"
+
+namespace ntp_snippets {
+
+NTPSnippetsStatusService::NTPSnippetsStatusService(
+    SigninManagerBase* signin_manager,
+    sync_driver::SyncService* sync_service)
+    : disabled_reason_(DisabledReason::EXPLICITLY_DISABLED),
+      signin_manager_(signin_manager),
+      sync_service_(sync_service),
+      sync_service_observer_(this) {}
+
+NTPSnippetsStatusService::~NTPSnippetsStatusService() {
+  if (disabled_reason_change_callback_.is_null())
+    return;
+
+  disabled_reason_change_callback_.Reset();

[Bernhard Bauer, 2016/06/28 13:47:39]

This isn't really necessary -- no one is going to access this after the
destructor has run, and then the member will be destroyed anyway.

[dgn, 2016/06/28 16:38:57]

Done.

+  sync_service_observer_.Remove(sync_service_);

[Bernhard Bauer, 2016/06/28 13:47:39]

? The point of ScopedObserver is that it will unregister the observers on
destruction. If you remove the source, that will _not_ happen 😃

[dgn, 2016/06/28 16:38:57]

Moved over from NTPSnippetService but there it was done in shutdown, not
destructor. Removed.

[Bernhard Bauer, 2016/06/28 16:47:25]

Ah yes, ScopedObserver::Remove will actually remove the observer, but if we now
continue observing, that's indeed not necessary.

+}
+
+void NTPSnippetsStatusService::Init(
+    const DisabledReasonChangeCallback& callback) {
+  DCHECK(disabled_reason_change_callback_.is_null());
+
+  disabled_reason_change_callback_ = callback;
+
+  // Notify about the current state before registering the observer, to make
+  // sure we don't get a double notification due to an undefined start state.
+  disabled_reason_ = GetDisabledReasonFromDeps();
+  disabled_reason_change_callback_.Run(disabled_reason_);
+
+  sync_service_observer_.Add(sync_service_);
+}
+
+void NTPSnippetsStatusService::OnStateChanged() {
+  DisabledReason new_disabled_reason = GetDisabledReasonFromDeps();
+
+  if (new_disabled_reason == disabled_reason_)
+    return;
+
+  disabled_reason_ = new_disabled_reason;
+  disabled_reason_change_callback_.Run(disabled_reason_);
+}
+
+DisabledReason NTPSnippetsStatusService::GetDisabledReasonFromDeps() const {
+  if (!signin_manager_ || !signin_manager_->IsAuthenticated()) {
+    DVLOG(1) << "[GetNewDisabledReason] Signed out";
+    return DisabledReason::SIGNED_OUT;
+  }
+
+  if (!sync_service_ || !sync_service_->CanSyncStart()) {
+    DVLOG(1) << "[GetNewDisabledReason] Sync disabled";
+    return DisabledReason::SYNC_DISABLED;
+  }
+
+  // !IsSyncActive in cases where CanSyncStart is true hints at the backend not
+  // being initialized.
+  // ConfigurationDone() verifies that the sync service has properly loaded its
+  // configuration and is aware of the different data types to sync.
+  if (!sync_service_->IsSyncActive() || !sync_service_->ConfigurationDone()) {
+    DVLOG(1) << "[GetNewDisabledReason] Sync initialization is not complete.";
+    return DisabledReason::HISTORY_SYNC_STATE_UNKNOWN;
+  }
+
+  if (sync_service_->IsEncryptEverythingEnabled()) {
+    DVLOG(1) << "[GetNewDisabledReason] Encryption is enabled";
+    return DisabledReason::PASSPHRASE_ENCRYPTION_ENABLED;
+  }
+
+  if (!sync_service_->GetActiveDataTypes().Has(
+          syncer::HISTORY_DELETE_DIRECTIVES)) {
+    DVLOG(1) << "[GetNewDisabledReason] History sync disabled";
+    return DisabledReason::HISTORY_SYNC_DISABLED;
+  }
+
+  DVLOG(1) << "[GetNewDisabledReason] Enabled";
+  return DisabledReason::NONE;
+}
+
+}  // namespace ntp_snippets