lacros: Start lacros-chrome if it was running in the last session

Specifically, record a "launch_on_login" pref whenever lacros
successfully starts. Set the pref false when lacros terminates.

Prefs are flushed to disk periodically, so this means the pref is in
the right state even if ash-chrome crashes mid-session.

Bug: 1109050
Change-Id: If7ca21a570b73b56cbbef838cf59526034092b9e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2318648Reviewed-by: Erik Chen <erikchen@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791968}

chrome/browser/chromeos/crosapi/lacros_manager.cc

@@ -25,8 +25,10 @@
 #include "chrome/browser/chromeos/crosapi/lacros_loader.h"
 #include "chrome/browser/chromeos/crosapi/lacros_util.h"
 #include "chrome/browser/component_updater/cros_component_manager.h"
+#include "chrome/browser/profiles/profile_manager.h"
 #include "chromeos/constants/chromeos_features.h"
 #include "chromeos/constants/chromeos_switches.h"
+#include "components/prefs/pref_service.h"
 #include "components/session_manager/core/session_manager.h"
 #include "google_apis/google_api_keys.h"
 #include "mojo/public/cpp/bindings/pending_remote.h"
@@ -76,6 +78,16 @@ void TerminateLacrosChrome(base::Process process) {
   LOG_IF(ERROR, !success) << "Failed to terminate the lacros-chrome.";
 }
 
+void SetLaunchOnLoginPref(bool launch_on_login) {
+  ProfileManager::GetPrimaryUserProfile()->GetPrefs()->SetBoolean(
+      lacros_util::kLaunchOnLoginPref, launch_on_login);
+}
+
+bool GetLaunchOnLoginPref() {
+  return ProfileManager::GetPrimaryUserProfile()->GetPrefs()->GetBoolean(
+      lacros_util::kLaunchOnLoginPref);
+}
+
 }  // namespace
 
 // static
@@ -240,6 +252,10 @@ void LacrosManager::OnAshChromeServiceReceiverReceived(
   ash_chrome_service_ =
       std::make_unique<AshChromeServiceImpl>(std::move(pending_receiver));
   state_ = State::RUNNING;
+  // Set the launch-on-login pref every time lacros-chrome successfully starts,
+  // instead of once during ash-chrome shutdown, so we have the right value
+  // even if ash-chrome crashes.
+  SetLaunchOnLoginPref(true);
   LOG(WARNING) << "Connection to lacros-chrome is established.";
 }
 
@@ -262,6 +278,9 @@ void LacrosManager::OnLacrosChromeTerminated() {
   DCHECK_EQ(state_, State::TERMINATING);
   LOG(WARNING) << "Lacros-chrome is terminated";
   state_ = State::STOPPED;
+  // TODO(https://crbug.com/1109366): Restart lacros-chrome if it exits
+  // abnormally (e.g. crashes). For now, assume the user meant to close it.
+  SetLaunchOnLoginPref(false);
 }
 
 void LacrosManager::OnUserSessionStarted(bool is_primary_user) {
@@ -299,4 +318,8 @@ void LacrosManager::OnLoadComplete(const base::FilePath& path) {
     const bool success = !path.empty();
     std::move(load_complete_callback_).Run(success);
   }
+
+  if (state_ == State::STOPPED && GetLaunchOnLoginPref()) {
+    Start();
+  }
 }

chrome/browser/chromeos/crosapi/lacros_util.cc

@@ -10,6 +10,7 @@
 #include "base/system/sys_info.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_paths.h"
+#include "components/prefs/pref_registry_simple.h"
 #include "components/user_manager/user.h"
 #include "components/user_manager/user_manager.h"
 #include "components/user_manager/user_type.h"
@@ -42,6 +43,12 @@ bool IsUserTypeAllowed(const User* user) {
 
 }  // namespace
 
+const char kLaunchOnLoginPref[] = "lacros.launch_on_login";
+
+void RegisterProfilePrefs(PrefRegistrySimple* registry) {
+  registry->RegisterBooleanPref(kLaunchOnLoginPref, /*default_value=*/false);
+}
+
 base::FilePath GetUserDataDir() {
   base::FilePath base_path;
   if (base::SysInfo::IsRunningOnChromeOS()) {

chrome/browser/chromeos/crosapi/lacros_util.h

@@ -5,6 +5,8 @@
 #ifndef CHROME_BROWSER_CHROMEOS_CROSAPI_LACROS_UTIL_H_
 #define CHROME_BROWSER_CHROMEOS_CROSAPI_LACROS_UTIL_H_
 
+class PrefRegistrySimple;
+
 namespace base {
 class FilePath;
 }  // namespace base
@@ -15,6 +17,12 @@ enum class Channel;
 
 namespace lacros_util {
 
+// Boolean preference. Whether to launch lacros-chrome on login.
+extern const char kLaunchOnLoginPref[];
+
+// Registers user profile preferences related to the lacros-chrome binary.
+void RegisterProfilePrefs(PrefRegistrySimple* registry);
+
 // Returns the user directory for lacros-chrome.
 base::FilePath GetUserDataDir();
 

chrome/browser/chromeos/preferences.cc

@@ -27,6 +27,7 @@
 #include "chrome/browser/chromeos/accessibility/magnification_manager.h"
 #include "chrome/browser/chromeos/base/locale_util.h"
 #include "chrome/browser/chromeos/child_accounts/parent_access_code/parent_access_service.h"
+#include "chrome/browser/chromeos/crosapi/lacros_util.h"
 #include "chrome/browser/chromeos/drive/file_system_util.h"
 #include "chrome/browser/chromeos/first_run/help_app_first_run_field_trial.h"
 #include "chrome/browser/chromeos/input_method/input_method_syncer.h"
@@ -182,6 +183,7 @@ void Preferences::RegisterProfilePrefs(
   // Some classes register their own prefs.
   TurnSyncOnHelper::RegisterProfilePrefs(registry);
   input_method::InputMethodSyncer::RegisterProfilePrefs(registry);
+  lacros_util::RegisterProfilePrefs(registry);
 
   std::string hardware_keyboard_id;
   // TODO(yusukes): Remove the runtime hack.