Set skip Crostini restart when enabling Crostini for testing

This modifies the private autotest API so that when it sets Crostini to
be enabled that it also notifies the CrostiniRestarter that it should
skip its restart phases. This will enable testing of features that
integrate into the Chrome launcher without having to invoke the slower
Crostini startup process that Chrome uses.

BUG=chromium:849438
TEST=Verified on eve that launcher apps can start after this

Change-Id: Ieaf9f8d41b8e077fc0ae44bae5ec12da9dcfcf92
Reviewed-on: https://chromium-review.googlesource.com/1227185Reviewed-by: Nicholas Verne <nverne@chromium.org>
Reviewed-by: Ben Wells <benwells@chromium.org>
Commit-Queue: Jeffrey Kardatzke <jkardatzke@google.com>
Cr-Commit-Position: refs/heads/master@{#591924}

chrome/browser/extensions/api/autotest_private/autotest_private_api.cc

@@ -731,6 +731,12 @@ AutotestPrivateSetCrostiniEnabledFunction::Run() {
   // Set the preference to indicate Crostini is enabled/disabled.
   ProfileManager::GetActiveUserProfile()->GetPrefs()->SetBoolean(
       crostini::prefs::kCrostiniEnabled, params->enabled);
+  // Set the flag to indicate we are in testing mode so that Chrome doesn't
+  // try to start the VM/container itself.
+  crostini::CrostiniManager* crostini_manager =
+      crostini::CrostiniManager::GetForProfile(
+          ProfileManager::GetActiveUserProfile());
+  crostini_manager->set_skip_restart_for_testing();
   return RespondNow(NoArguments());
 #else
   return RespondNow(Error(kOnlyAvailableOnChromeOSError));