Fix browser crash when enabling managed extensions in incognito.

DisableExtension is aborting early for managed extensions because the user is not allowed to disable managed extensions, which causes a CHECK() to fail. However, it should be ok to disable managed extensions for reload purposes.

BUG=249294

Review URL: https://chromiumcodereview.appspot.com/17451006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207532 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index d4f0e9a5..de08717c 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -888,6 +888,7 @@
   // |extension| can be NULL if sync disables an extension that is not
   // installed yet.
   if (extension &&
+      disable_reason != Extension::DISABLE_RELOAD &&
       !system_->management_policy()->UserMayModifySettings(extension, NULL)) {
     return;
   }