Unit test break fix.

TEST=BackgroundApplicationListModelTest.LoadExplicitExtensions should pass on ChromeOS now
BUG=none
TBR=stevenjb
Review URL: http://codereview.chromium.org/6869040

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@81872 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index 7dcba6e0a..0847821 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -1086,8 +1086,11 @@
         RevokeRightsForExtension(extension);
 #if defined(OS_CHROMEOS)
     // Revoke external file access to
-    profile_->GetFileSystemContext()->path_manager()->external_provider()->
-        RevokeAccessForExtension(extension->id());
+    if (profile_->GetFileSystemContext()->path_manager() &&
+        profile_->GetFileSystemContext()->path_manager()->external_provider()) {
+      profile_->GetFileSystemContext()->path_manager()->external_provider()->
+          RevokeAccessForExtension(extension->id());
+    }
 #endif
   }