[Sync] Implement encryption-aware conflict resolution.

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

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sync/profile_sync_service_harness.h"
 #include "chrome/browser/sync/sessions/session_state.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"
 #include "chrome/browser/sync/test/integration/sessions_helper.h"
@@ skipping 238 matching lines @@
       GetClient(1)->GetLastSessionSnapshot()->
       num_conflicting_updates);  // The encrypted nodes.
 
   // These changes are either made with the old passphrase or not encrypted at
   // all depending on when client 0's changes are propagated.
   ScopedWindowMap client1_windows;
   ASSERT_TRUE(OpenTabAndGetLocalWindows(1, GURL(kURL1),
       client1_windows.GetMutable()));
 
   // At this point we enter the passphrase, triggering a resync, in which the
-  // local changes of client 1 get overwritten for now.
+  // local changes of client 1 get sent to client 0.
   GetClient(1)->service()->SetPassphrase(kValidPassphrase, true);
   ASSERT_TRUE(GetClient(1)->AwaitPassphraseAccepted());
   ASSERT_TRUE(GetClient(1)->WaitForTypeEncryption(syncable::SESSIONS));
+  ASSERT_TRUE(GetClient(1)->AwaitMutualSyncCycleCompletion(GetClient(0)));
   ASSERT_EQ(0, GetClient(1)->GetLastSessionSnapshot()->
       num_conflicting_updates);
 
   ASSERT_TRUE(IsEncrypted(0, syncable::SESSIONS));
   ASSERT_TRUE(IsEncrypted(1, syncable::SESSIONS));
-  // The session data from client 1 got overwritten. As a result, client 0
-  // should have no foreign session data. TODO(zea): update this once bug 76596
-  // is resolved and we don't choose server wins on encryption conflicts.
   SyncedSessionVector sessions0;
   SyncedSessionVector sessions1;
-  ASSERT_FALSE(GetSessionData(0, &sessions0));
+  ASSERT_TRUE(GetSessionData(0, &sessions0));
   ASSERT_FALSE(GetSessionData(1, &sessions1));
 }
 
 // Flaky. http://crbug.com/85294
 IN_PROC_BROWSER_TEST_F(TwoClientSessionsSyncTest,
                        FLAKY_SecondChangesBeforeEncrAndPassphraseChange) {
   ASSERT_TRUE(SetupSync()) << "SetupSync() failed.";
 
   ASSERT_TRUE(CheckInitialState(0));
   ASSERT_TRUE(CheckInitialState(1));
@@ skipping 142 matching lines @@
   ASSERT_FALSE(GetSessionData(1, &sessions1));
 
   // Client 0 becomes active again with a new tab.
   ASSERT_TRUE(OpenTabAndGetLocalWindows(0, GURL(kURL2),
       client0_windows.GetMutable()));
   ASSERT_TRUE(GetClient(0)->AwaitMutualSyncCycleCompletion(GetClient(1)));
   ASSERT_TRUE(GetSessionData(1, &sessions1));
   ASSERT_EQ(1U, sessions1.size());
   ASSERT_TRUE(WindowsMatch(sessions1[0]->windows, *client0_windows.Get()));
 }