[sync] "TwoClientBookmarksSyncTest.Sanity" is flaky

chrome/browser/sync/test/integration/single_client_sessions_sync_test.cc

Index: chrome/browser/sync/test/integration/single_client_sessions_sync_test.cc
diff --git a/chrome/browser/sync/test/integration/single_client_sessions_sync_test.cc b/chrome/browser/sync/test/integration/single_client_sessions_sync_test.cc
index 0f99199245b81c5f562d2275a2059808a4bc9010..c395ef3533f65f357093efe535c9cf8a0042c0a9 100644
--- a/chrome/browser/sync/test/integration/single_client_sessions_sync_test.cc
+++ b/chrome/browser/sync/test/integration/single_client_sessions_sync_test.cc
@@ -10,11 +10,13 @@
 #include "chrome/browser/sync/test/integration/sync_test.h"
 #include "chrome/browser/sync/test/integration/typed_urls_helper.h"
 #include "chrome/browser/sync/test/integration/updated_progress_marker_checker.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/url_constants.h"
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/history/core/browser/history_types.h"
 #include "components/sessions/core/session_types.h"
 #include "components/sync/base/time.h"
+#include "components/sync/driver/sync_driver_switches.h"
 #include "components/sync/test/fake_server/fake_server_verifier.h"
 #include "components/sync/test/fake_server/sessions_hierarchy.h"
 
@@ -36,6 +38,18 @@ class SingleClientSessionsSyncTest : public SyncTest {
   SingleClientSessionsSyncTest() : SyncTest(SINGLE_CLIENT) {}
   ~SingleClientSessionsSyncTest() override {}
 
+  void SetUpCommandLine(base::CommandLine* cl) override {
+    // This is a hacky override of the switches set in
+    // SyncTest::SetUpCommandLine() to avoid the switch that speeds up nudge
+    // delays. CookieJarMismatch asserts exact histogram counts assuming that

[Nicolas Zea, 2016/11/09 00:35:13]

Hmm, what's the issue with CookieJarMismatch? Ideally it shouldn't depend on
slow syncs.

[Patrick Noland, 2016/11/10 22:13:00]

SessionsHelper waits for a title to load before deciding a tab is loaded when
calling OpenTabAndGetLocalWindows. SessionsSyncManager doesn't care if the title
is present or not, so it can plausibly commit the title-less tab, trigering the
histogram logic, then commit again once the title shows up. 

+    // sync is (relatively) slow, so we preserve that assumption.
+    if (!cl->HasSwitch(switches::kDisableBackgroundNetworking))
+      cl->AppendSwitch(switches::kDisableBackgroundNetworking);
+
+    if (!cl->HasSwitch(switches::kSyncShortInitialRetryOverride))
+      cl->AppendSwitch(switches::kSyncShortInitialRetryOverride);
+  }
+
  private:
   DISALLOW_COPY_AND_ASSIGN(SingleClientSessionsSyncTest);
 };