UKM Sync Observer

components/ukm/observers/sync_disable_observer.cc

Index: components/ukm/observers/sync_disable_observer.cc
diff --git a/components/ukm/observers/sync_disable_observer.cc b/components/ukm/observers/sync_disable_observer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ccba78c9170f36782db50056e936ad12fd0ec080
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+++ b/components/ukm/observers/sync_disable_observer.cc
@@ -0,0 +1,81 @@
+// Copyright 2017 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/ukm/observers/sync_disable_observer.h"
+
+#include "base/stl_util.h"
+
+namespace ukm {
+
+SyncDisableObserver::SyncDisableObserver()
+    : sync_observer_(this), all_profiles_enabled_(false) {}
+
+SyncDisableObserver::~SyncDisableObserver() {}
+
+// static
+SyncDisableObserver::SyncState SyncDisableObserver::GetSyncState(
+    syncer::SyncService* sync_service) {
+  return SyncDisableObserver::SyncState{
+      .history_enabled = sync_service->GetPreferredDataTypes().Has(
+          syncer::HISTORY_DELETE_DIRECTIVES),
+      .initialized = sync_service->IsEngineInitialized(),
+      .passphrase_protected = sync_service->IsUsingSecondaryPassphrase(),
+  };
+}
+
+void SyncDisableObserver::ObserveServiceForSyncDisables(
+    syncer::SyncService* sync_service) {
+  previous_states_[sync_service] = GetSyncState(sync_service);
+  sync_observer_.Add(sync_service);
+  UpdateAllProfileEnabled(false);
+}
+
+void SyncDisableObserver::UpdateAllProfileEnabled(bool must_purge) {
+  bool all_enabled = AreAllProfilesEnabled();
+  if (must_purge || (all_enabled != all_profiles_enabled_)) {
+    all_profiles_enabled_ = all_enabled;
+    OnSyncPrefsChanged(must_purge);
+  }
+}
+
+bool SyncDisableObserver::AreAllProfilesEnabled() {
+  if (previous_states_.empty())
+    return false;
+  for (const auto& kv : previous_states_) {
+    const SyncDisableObserver::SyncState& state = kv.second;
+    if (!state.history_enabled || !state.initialized ||
+        state.passphrase_protected)
+      return false;
+  }
+  return true;
+}
+
+void SyncDisableObserver::OnStateChanged(syncer::SyncService* sync) {
+  DCHECK(base::ContainsKey(previous_states_, sync));
+  SyncDisableObserver::SyncState state = GetSyncState(sync);
+  const SyncDisableObserver::SyncState& previous_state = previous_states_[sync];
+  bool must_purge =
+      // Trigger a purge if history sync was disabled.
+      (previous_state.history_enabled && !state.history_enabled) ||
+      // Trigger a purge if the user added a passphrase.  Since we can't detect
+      // the use of a passphrase while the engine is not initialized, we may
+      // miss the transition if the user adds a passphrase in this state.
+      (previous_state.initialized && state.initialized &&
+       !previous_state.passphrase_protected && state.passphrase_protected);
+  previous_states_[sync] = state;
+  UpdateAllProfileEnabled(must_purge);
+}
+
+void SyncDisableObserver::OnSyncShutdown(syncer::SyncService* sync) {
+  DCHECK(base::ContainsKey(previous_states_, sync));
+  sync_observer_.Remove(sync);
+  previous_states_.erase(sync);
+  UpdateAllProfileEnabled(false);
+}
+
+bool SyncDisableObserver::IsHistorySyncEnabledOnAllProfiles() {
+  return all_profiles_enabled_;
+}
+
+}  // namespace ukm