PreferencesManager

chrome/browser/prefs/preferences_connection_manager.cc

+// 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 "chrome/browser/prefs/preferences_connection_manager.h"
+
+#include "chrome/browser/prefs/preferences_manager.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
+#include "components/keyed_service/content/browser_context_keyed_service_shutdown_notifier_factory.h"
+
+namespace {
+
+// Required singleton subclass to control dependencies between
+// PreferenceConnectionManager and the KeyedServiceShutdownNotifier.
+class ShutdownNotifierFactory
+    : public BrowserContextKeyedServiceShutdownNotifierFactory {
+ public:
+  static ShutdownNotifierFactory* GetInstance() {
+    return base::Singleton<ShutdownNotifierFactory>::get();
+  }
+
+ private:
+  friend struct base::DefaultSingletonTraits<ShutdownNotifierFactory>;
+
+  ShutdownNotifierFactory()
+      : BrowserContextKeyedServiceShutdownNotifierFactory(
+            "PreferencesConnectionManager") {
+    DependsOn(ProfileOAuth2TokenServiceFactory::GetInstance());
+  }
+  ~ShutdownNotifierFactory() override {}
+
+  DISALLOW_COPY_AND_ASSIGN(ShutdownNotifierFactory);
+};
+
+}  // namespace
+
+namespace chrome {
+
+PreferencesConnectionManager::PreferencesConnectionManager()
+    : profile_shutdown_notification_(
+          ShutdownNotifierFactory::GetInstance()
+              ->Get(ProfileManager::GetActiveUserProfile())
+              ->Subscribe(
+                  base::Bind(&PreferencesConnectionManager::OnProfileDestroyed,
+                             base::Unretained(this)))) {}
+
+PreferencesConnectionManager::~PreferencesConnectionManager() {}
+
+void PreferencesConnectionManager::ProcessRequest(
+    prefs::mojom::PreferencesManagerRequest request) {
+  Profile* profile = ProfileManager::GetActiveUserProfile();
+  mojo::StrongBindingPtr<prefs::mojom::PreferencesManager> binding =
+      mojo::MakeStrongBinding(base::MakeUnique<PreferencesManager>(profile),

[msw, 2016/11/18 00:32:57]

I wonder if a single PreferencesManager instance could just manage a BindingSet
instead?

[jonross, 2016/11/18 00:47:58]

I originally had that, but wanted to handle different services listening to the
same pref. So that one could set a new value, receive no notification, while
others who didn't request the change receive an update.

The StrongBindingPtr also nicely handles onConnectionError automatically.

+                              std::move(request));
+  bindings_.push_back(binding);
+}
+
+void PreferencesConnectionManager::OnProfileDestroyed() {
+  for (auto it : bindings_) {

[James Cook, 2016/11/18 00:50:34]

auto& ?  auto* ?

Otherwise the copying (or not) isn't clear.

[jonross, 2016/11/18 20:31:23]

Done.

+    // Check that the PreferencesManager was not cleared from a connection
+    // error.
+    if (it)
+      (static_cast<PreferencesManager*>(it->impl()))->OnProfileDestroyed();
+  }
+
+  profile_shutdown_notification_.reset();
+}
+
+}  // namespace chrome