Start the migration of passwords from the Keychain.

chrome/browser/password_manager/password_store_proxy_mac.cc

Index: chrome/browser/password_manager/password_store_proxy_mac.cc
diff --git a/chrome/browser/password_manager/password_store_proxy_mac.cc b/chrome/browser/password_manager/password_store_proxy_mac.cc
index 2d16b7ecfef43b1104d789ce34c678d0ad4f26a1..e715529e0e26f4fe8f3df69b3a4e65c5eca18600 100644
--- a/chrome/browser/password_manager/password_store_proxy_mac.cc
+++ b/chrome/browser/password_manager/password_store_proxy_mac.cc
@@ -4,23 +4,34 @@
 
 #include "chrome/browser/password_manager/password_store_proxy_mac.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "chrome/browser/password_manager/password_store_mac.h"
 #include "chrome/browser/password_manager/simple_password_store_mac.h"
 #include "content/public/browser/browser_thread.h"
 #include "crypto/apple_keychain.h"
 
+using password_manager::MigrationStatus;
 using password_manager::PasswordStoreChangeList;
 
 PasswordStoreProxyMac::PasswordStoreProxyMac(
     scoped_refptr<base::SingleThreadTaskRunner> main_thread_runner,
     scoped_ptr<crypto::AppleKeychain> keychain,
-    scoped_ptr<password_manager::LoginDatabase> login_db)
+    scoped_ptr<password_manager::LoginDatabase> login_db,
+    PrefService* prefs)
     : PasswordStore(main_thread_runner, nullptr),
       login_metadata_db_(login_db.Pass()) {
   DCHECK(login_metadata_db_);
-  // TODO(vasilii): for now the class is just a wrapper around PasswordStoreMac.
-  password_store_mac_ =
-      new PasswordStoreMac(main_thread_runner, nullptr, keychain.Pass());
+  migration_status_.Init(password_manager::prefs::kKeychainMigrationStatus,
+                         prefs);
+  if (migration_status_.GetValue() ==
+      static_cast<int>(MigrationStatus::MIGRATED)) {
+    // The login database will be set later after initialization.
+    password_store_simple_ =
+        new SimplePasswordStoreMac(main_thread_runner, nullptr, nullptr);
+  } else {
+    password_store_mac_ =
+        new PasswordStoreMac(main_thread_runner, nullptr, keychain.Pass());
+  }
 }
 
 PasswordStoreProxyMac::~PasswordStoreProxyMac() {
@@ -37,17 +48,27 @@ bool PasswordStoreProxyMac::Init(
     return false;
   }
 
-  ScheduleTask(
-      base::Bind(&PasswordStoreProxyMac::InitOnBackgroundThread, this));
-  password_store_mac_->InitWithTaskRunner(GetBackgroundTaskRunner());
-  return password_manager::PasswordStore::Init(flare);
+  if (!password_manager::PasswordStore::Init(flare))
+    return false;
+
+  return ScheduleTask(
+      base::Bind(&PasswordStoreProxyMac::InitOnBackgroundThread, this,
+                 static_cast<MigrationStatus>(migration_status_.GetValue())));
 }
 
 void PasswordStoreProxyMac::Shutdown() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   PasswordStore::Shutdown();
-  GetBackend()->Shutdown();
   thread_->Stop();
+
+  // Execute the task which are still pending.
+  FlushPendingTasks();
+
+  // Unsubscribe the observer, otherwise it's too late in the destructor.
+  migration_status_.Destroy();
+
+  // After the thread has stopped, the backend can't change.

[vabr (Chromium), 2015/07/06 09:50:19]

I'm a bit unclear about what the comment tries to say. Is it defending shutting
down the backend here? Or does it say that the backend cannot do anything after
line 62 above? The latter is a bit confusing (can it still shut down?), so
please explain.

[vasilii, 2015/07/06 13:57:57]

Done.

+  GetBackend()->Shutdown();
 }
 
 scoped_refptr<base::SingleThreadTaskRunner>
@@ -61,15 +82,62 @@ password_manager::PasswordStore* PasswordStoreProxyMac::GetBackend() const {
   return password_store_simple_.get();
 }
 
-void PasswordStoreProxyMac::InitOnBackgroundThread() {
+void PasswordStoreProxyMac::InitOnBackgroundThread(MigrationStatus status) {
   DCHECK(GetBackgroundTaskRunner()->BelongsToCurrentThread());
   if (!login_metadata_db_->Init()) {
     login_metadata_db_.reset();
     LOG(ERROR) << "Could not create/open login database.";
-    return;
   }
-  if (password_store_mac_)
+
+  if (status == MigrationStatus::MIGRATED) {
+    password_store_simple_->InitWithTaskRunner(GetBackgroundTaskRunner(),
+                                               login_metadata_db_.Pass());
+  } else {
     password_store_mac_->set_login_metadata_db(login_metadata_db_.get());
+    password_store_mac_->InitWithTaskRunner(GetBackgroundTaskRunner());
+    if (login_metadata_db_ && (status == MigrationStatus::NOT_STARTED ||
+                               status == MigrationStatus::FAILED_ONCE)) {
+      // Let's try to migrate the passwords.
+      if (password_store_mac_->ImportFromKeychain() ==
+          PasswordStoreMac::MIGRATION_OK) {
+        status = MigrationStatus::MIGRATED;
+        // Switch from |password_store_mac_| to |password_store_simple_|.
+        password_store_mac_->set_login_metadata_db(nullptr);
+        pending_ui_tasks_.push_back(
+            base::Bind(&PasswordStoreMac::Shutdown, password_store_mac_));
+        password_store_mac_ = nullptr;
+        password_store_simple_ = new SimplePasswordStoreMac(
+            main_thread_runner_, GetBackgroundTaskRunner(),
+            login_metadata_db_.Pass());
+      } else {
+        status = (status == MigrationStatus::FAILED_ONCE
+                      ? MigrationStatus::FAILED_TWICE
+                      : MigrationStatus::FAILED_ONCE);
+      }
+      pending_ui_tasks_.push_back(
+          base::Bind(&PasswordStoreProxyMac::UpdateStatusPref, this, status));
+    }
+  }
+  if (!pending_ui_tasks_.empty()) {
+    main_thread_runner_->PostTask(
+        FROM_HERE, base::Bind(&PasswordStoreProxyMac::FlushPendingTasks, this));
+  }
+  UMA_HISTOGRAM_ENUMERATION(
+      "PasswordManager.KeychainMigration.Status", static_cast<int>(status),
+      static_cast<int>(MigrationStatus::NUM_MIGRATION_STATUS));
+  DCHECK(GetBackend());
+}
+
+void PasswordStoreProxyMac::UpdateStatusPref(MigrationStatus status) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  migration_status_.SetValue(static_cast<int>(status));
+}
+
+void PasswordStoreProxyMac::FlushPendingTasks() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  for (auto& task : pending_ui_tasks_)
+    task.Run();
+  pending_ui_tasks_.clear();
 }
 
 void PasswordStoreProxyMac::ReportMetricsImpl(