Create setting that disables password stores

chrome/browser/password_manager/password_store_factory.cc

Index: chrome/browser/password_manager/password_store_factory.cc
diff --git a/chrome/browser/password_manager/password_store_factory.cc b/chrome/browser/password_manager/password_store_factory.cc
index 088ff7e885746cd63ed062393f5800275e6a8998..dde91271afd398cadda762b03e442f87b1b78f56 100644
--- a/chrome/browser/password_manager/password_store_factory.cc
+++ b/chrome/browser/password_manager/password_store_factory.cc
@@ -21,6 +21,7 @@
 #include "chrome/browser/sync/glue/sync_start_util.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/browser/web_data_service_factory.h"
+#include "chrome/common/chrome_paths_internal.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
@@ -127,7 +128,7 @@ PasswordStoreFactory::PasswordStoreFactory()
   DependsOn(WebDataServiceFactory::GetInstance());
 #if defined(OS_WIN) || defined(OS_MACOSX) || \
     (defined(OS_LINUX) && !defined(OS_CHROMEOS))
-  // TODO(crbug.com/715987). Remove when PasswordReuseDetector is decoupled

[vabr (Chromium), 2017/07/03 19:27:14]

nit: Let's stick to changes related with the CL goal. Fixing the typo here will
make git blame for this line one step longer.

[cfroussios, 2017/07/04 09:58:15]

Done.

+  // TODO(crbug.com/715987) Remove when PasswordReuseDetector is decoupled
   // from PasswordStore.
   DependsOn(SigninManagerFactory::GetInstance());
 #endif
@@ -206,8 +207,14 @@ PasswordStoreFactory::BuildServiceInstanceFor(
   PrefService* prefs = profile->GetPrefs();
   LocalProfileId id = GetLocalProfileId(prefs);
 
+  bool use_preference = base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableEncryptionSelection);
+  base::FilePath user_data_dir;
+  chrome::GetDefaultUserDataDirectory(&user_data_dir);

[vabr (Chromium), 2017/07/03 19:27:14]

optional: GetDefaultUserDataDirectory does not look completely simple inside,
not sure if it is expensive to compute. In case it were expensive, the
alternative would be to only call it if |use_preference| is true.

[cfroussios, 2017/07/04 09:58:15]

Done.

+  bool use_backend = !use_preference || os_crypt::GetBackendUse(user_data_dir);
+
   os_crypt::SelectedLinuxBackend selected_backend =
-      os_crypt::SelectBackend(store_type, desktop_env);
+      os_crypt::SelectBackend(store_type, use_backend, desktop_env);
 
   std::unique_ptr<PasswordStoreX::NativeBackend> backend;
   if (selected_backend == os_crypt::SelectedLinuxBackend::KWALLET ||