Depend on stored sync session GUID for Android.

chrome/browser/sync/glue/session_model_associator.cc

 // Copyright (c) 2012 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 "chrome/browser/sync/glue/session_model_associator.h"
 
 #include <algorithm>
 #include <set>
 #include <utility>
 
@@ skipping 30 matching lines @@
 #include "sync/protocol/session_specifics.pb.h"
 #include "sync/syncable/directory.h"
 #include "sync/syncable/read_transaction.h"
 #include "sync/syncable/write_transaction.h"
 #include "sync/util/get_session_name.h"
 #include "ui/gfx/favicon_size.h"
 #if defined(OS_LINUX)
 #include "base/linux_util.h"
 #elif defined(OS_WIN)
 #include <windows.h>
-#elif defined(OS_ANDROID)
-#include "sync/util/session_utils_android.h"
 #endif
 
 using content::BrowserThread;
 using content::NavigationEntry;
 using prefs::kSyncSessionsGUID;
 using syncer::SESSIONS;
 
 namespace browser_sync {
 
 namespace {
@@ skipping 573 matching lines @@
       write_node.SetTitle(UTF8ToWide(current_machine_tag_));
       sync_pb::SessionSpecifics base_specifics;
       base_specifics.set_session_tag(current_machine_tag_);
       sync_pb::SessionHeader* header_s = base_specifics.mutable_header();
       header_s->set_client_name(current_session_name_);
       header_s->set_device_type(DeviceInfo::GetLocalDeviceType());
       write_node.SetSessionSpecifics(base_specifics);
 
       local_session_syncid_ = write_node.GetId();
     }
+#if defined(OS_ANDROID)
+    std::string persisted_machine_tag;

[Nicolas Zea, 2012/11/16 18:55:20]

I don't think you need this variable, doesn't current_machine_tag_ already hold
the same string?

[nyquist, 2012/12/04 01:55:05]

Done.

+    if (pref_service_)
+      persisted_machine_tag = pref_service_->GetString(kSyncSessionsGUID);
+
+    std::string transaction_tag = GetMachineTagFromTransaction(&trans);
+    if (persisted_machine_tag.compare(transaction_tag) != 0) {
+      DeleteForeignSession(transaction_tag);
+    }
+#endif
   }
 
   // Check if anything has changed on the client side.
   if (!UpdateSyncModelDataFromClient(&error)) {
     DCHECK(error.IsSet());
     return error;
   }
 
   DVLOG(1) << "Session models associated.";
   DCHECK(!error.IsSet());
@@ skipping 27 matching lines @@
   DCHECK(CalledOnValidThread());
   DCHECK(current_machine_tag_.empty());
   std::string persisted_guid;
   if (pref_service_)
     persisted_guid = pref_service_->GetString(kSyncSessionsGUID);
   if (!persisted_guid.empty()) {
     current_machine_tag_ = persisted_guid;
     DVLOG(1) << "Restoring persisted session sync guid: "
              << persisted_guid;
   } else {
-    syncer::syncable::Directory* dir =
-        trans->GetWrappedWriteTrans()->directory();
-    current_machine_tag_ = "session_sync";
-#if defined(OS_ANDROID)
-    const std::string android_id = syncer::internal::GetAndroidId();
-    // There are reports that sometimes the android_id can't be read. Those
-    // are supposed to be fixed as of Gingerbread, but if it happens we fall
-    // back to use the same GUID generation as on other platforms.
-    current_machine_tag_.append(android_id.empty() ?
-                                    dir->cache_guid() : android_id);
-#else
-    current_machine_tag_.append(dir->cache_guid());
-#endif
+    current_machine_tag_ = GetMachineTagFromTransaction(trans);
     DVLOG(1) << "Creating session sync guid: " << current_machine_tag_;
     if (pref_service_)
       pref_service_->SetString(kSyncSessionsGUID, current_machine_tag_);
   }
 
   tab_pool_.set_machine_tag(current_machine_tag_);
 }
 
 void SessionModelAssociator::OnSessionNameInitialized(
     const std::string& name) {
@@ skipping 559 matching lines @@
       return false;
     if (entry->GetVirtualURL().is_valid() &&
         !entry->GetVirtualURL().SchemeIs("chrome") &&
         !entry->GetVirtualURL().SchemeIsFile()) {
       found_valid_url = true;
     }
   }
   return found_valid_url;
 }
 
+std::string SessionModelAssociator::GetMachineTagFromTransaction(

[Nicolas Zea, 2012/11/16 18:55:20]

Since this is basically a static helper method, I think having it at the top of
the file in an anon namespace is better than a private member.

[nyquist, 2012/12/04 01:55:05]

Done.

+    syncer::WriteTransaction* trans) {
+  syncer::syncable::Directory* dir = trans->GetWrappedWriteTrans()->directory();
+  std::string machine_tag = "session_sync";
+  machine_tag.append(dir->cache_guid());
+  return machine_tag;
+}
+
 // If this functionality changes, SyncedSession::ShouldSyncSessionTab should be
 // modified to match.
 bool SessionModelAssociator::ShouldSyncTab(const SyncedTabDelegate& tab) const {
   DCHECK(CalledOnValidThread());
   if (!IsValidTab(tab))
     return false;
   return TabHasValidEntry(tab);
 }
 
 void SessionModelAssociator::QuitLoopForSubtleTesting() {
@@ skipping 19 matching lines @@
 
 bool SessionModelAssociator::CryptoReadyIfNecessary() {
   // We only access the cryptographer while holding a transaction.
   syncer::ReadTransaction trans(FROM_HERE, sync_service_->GetUserShare());
   const syncer::ModelTypeSet encrypted_types = trans.GetEncryptedTypes();
   return !encrypted_types.Has(SESSIONS) ||
          sync_service_->IsCryptographerReady(&trans);
 }
 
 }  // namespace browser_sync