Add pref to enable/disable palette tray.

chrome/browser/ui/ash/palette_delegate_chromeos.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/ui/ash/palette_delegate_chromeos.h"
 
+#include "ash/shell.h"
+#include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/chromeos/profiles/profile_helper.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/common/pref_names.h"
+#include "components/prefs/pref_change_registrar.h"
+#include "components/prefs/pref_service.h"
+#include "components/user_manager/user_manager.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_source.h"
+
 namespace chromeos {
 
-PaletteDelegateChromeOS::PaletteDelegateChromeOS() {}
+PaletteDelegateChromeOS::PaletteDelegateChromeOS() {
+  registrar_.Add(this, chrome::NOTIFICATION_SESSION_STARTED,
+                 content::NotificationService::AllSources());
+  registrar_.Add(this, chrome::NOTIFICATION_PROFILE_DESTROYED,
+                 content::NotificationService::AllSources());
+}
 
 PaletteDelegateChromeOS::~PaletteDelegateChromeOS() {}
 
+std::unique_ptr<PaletteDelegateChromeOS::EnableListenerSubscription>
+PaletteDelegateChromeOS::AddPaletteEnableListener(
+    const EnableListener& on_state_changed) {
+  auto subscription = callback_list_.Add(on_state_changed);
+  OnPaletteEnabledPrefChanged();
+  return subscription;
+}
+
+void PaletteDelegateChromeOS::ActiveUserChanged(const AccountId& account_id) {
+  const user_manager::User* user =
+      user_manager::UserManager::Get()->FindUser(account_id);
+  Profile* profile = ProfileHelper::Get()->GetProfileByUser(user);
+  SetProfile(profile);
+}
+
+void PaletteDelegateChromeOS::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  switch (type) {
+    case chrome::NOTIFICATION_SESSION_STARTED:
+      // Update |profile_| when entering a session.
+      SetProfile(ProfileManager::GetActiveUserProfile());
+
+      // Add a session state observer to be able to monitor session changes.
+      if (!session_state_observer_.get() && ash::Shell::HasInstance()) {
+        session_state_observer_.reset(
+            new ash::ScopedSessionStateObserver(this));
+      }
+      break;
+    case chrome::NOTIFICATION_PROFILE_DESTROYED: {
+      // Update |profile_| when exiting a session or shutting down.
+      Profile* profile = content::Source<Profile>(source).ptr();
+      if (profile_ == profile)
+        SetProfile(nullptr);
+      break;
+    }
+  }
+}
+
+void PaletteDelegateChromeOS::OnPaletteEnabledPrefChanged() {
+  if (profile_) {
+    callback_list_.Notify(
+        profile_->GetPrefs()->GetBoolean(prefs::kEnableAshPalette));
+  }
+}
+
+void PaletteDelegateChromeOS::SetProfile(Profile* profile) {
+  profile_ = profile;
+  pref_change_registrar_.reset();
+
+  if (profile_) {

[stevenjb, 2016/08/23 17:36:41]

if (!profile_) return;

[jdufault, 2016/08/23 22:49:56]

Done.

+    PrefService* prefs = profile_->GetPrefs();
+    pref_change_registrar_.reset(new PrefChangeRegistrar);
+    pref_change_registrar_->Init(prefs);
+    pref_change_registrar_->Add(
+        prefs::kEnableAshPalette,
+        base::Bind(&PaletteDelegateChromeOS::OnPaletteEnabledPrefChanged,
+                   base::Unretained(this)));
+
+    // Run listener with new pref value, if any.
+    OnPaletteEnabledPrefChanged();
+  }
+}
+
 }  // namespace chromeos