arc: Fix situation when ARC cannot be disabled safely.

chrome/browser/chromeos/arc/arc_session_manager.cc

Index: chrome/browser/chromeos/arc/arc_session_manager.cc
diff --git a/chrome/browser/chromeos/arc/arc_session_manager.cc b/chrome/browser/chromeos/arc/arc_session_manager.cc
index 3544f007a7645d368c16cdb8ec58aa1cd3f15a64..4c0c75381a1401110bfacb5b9d449686e63733c3 100644
--- a/chrome/browser/chromeos/arc/arc_session_manager.cc
+++ b/chrome/browser/chromeos/arc/arc_session_manager.cc
@@ -282,6 +282,17 @@ void ArcSessionManager::MaybeReenableArc() {
 void ArcSessionManager::OnProvisioningFinished(ProvisioningResult result) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
+  // If the Mojo message to notify finishing the provisioning is already sent
+  // from the container, it will be processed even after requesting to stop the
+  // container. Ignore all |result|s arriving while ARC is disabled, in order to
+  // avoid popping up an error message triggered below. This code intentionally
+  // does not support the case of reenabling.
+  if (!IsArcEnabled()) {
+    LOG(WARNING) << "Provisioning result received after Arc was disabled. "
+                 << "Ignoring result " << static_cast<int>(result) << ".";
+    return;
+  }
+
   // Due asynchronous nature of stopping the ARC instance,
   // OnProvisioningFinished may arrive after setting the |State::STOPPED| state
   // and |State::Active| is not guaranteed to be set here.
@@ -293,8 +304,8 @@ void ArcSessionManager::OnProvisioningFinished(ProvisioningResult result) {
     DCHECK_NE(result, ProvisioningResult::SUCCESS);
     // TODO (khmel): Consider changing LOG to NOTREACHED once we guaranty that
     // no double message can happen in production.
-    LOG(WARNING) << " Provisioning result was already reported. Ignoring "
-                 << " additional result " << static_cast<int>(result) << ".";
+    LOG(WARNING) << "Provisioning result was already reported. Ignoring "
+                 << "additional result " << static_cast<int>(result) << ".";
     return;
   }
   provisioning_reported_ = true;