nacl_integration: disable DNS prefetching and sync.

This eliminates possible sources of non-determinism in the integration tests.

BUG= none

Review URL: https://codereview.chromium.org/12213117

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@181946 0039d316-1c4b-4281-b951-d872f2087c98

ppapi/native_client/tools/browser_tester/browsertester/browserlauncher.py

@@ -271,6 +271,12 @@ class ChromeLauncher(BrowserLauncher):
             # Windows (see http://crbug.com/169941).
             '--disable-web-resources',
             '--disable-preconnect',
+            # This is speculative, sync should not occur with a clean profile.
+            '--disable-sync',
+            # This prevents Chrome from making "hidden" network requests at
+            # startup.  These requests could be a source of non-determinism,
+            # and they also add noise to the netlogs.
+            '--dns-prefetch-disable',
             '--no-first-run',
             '--no-default-browser-check',
             '--log-level=1',