[Sync] Add support for automatic enabling of syncing tab favicons.

We add the sync_tab_favicons field to the nigori node and add support
for automatically enabling the feature when we receive a new nigori node.
Once we do enable the feature, the browser will only start writing favicons
after the next restart.

BUG=92728
TEST=using python testserver to enable sync tab favicons, then restarting.


Review URL: http://codereview.chromium.org/10235013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@134184 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 14 insertions, 7 deletions

diff --git a/sync/internal_api/sync_manager.cc b/sync/internal_api/sync_manager.cc
index d7d8c8a..f33fefa 100644
--- a/sync/internal_api/sync_manager.cc
+++ b/sync/internal_api/sync_manager.cc
@@ -52,6 +52,7 @@
 #include "sync/syncable/model_type_payload_map.h"
 #include "sync/syncable/syncable.h"
 #include "sync/util/cryptographer.h"
+#include "sync/util/experiments.h"
 #include "sync/util/get_session_name.h"
 #include "sync/util/time.h"
 
@@ -2478,7 +2479,7 @@ syncable::ModelTypeSet SyncManager::GetEncryptedDataTypesForTest() const {
   return GetEncryptedTypes(&trans);
 }
 
-bool SyncManager::ReceivedExperimentalTypes(syncable::ModelTypeSet* to_add)
+bool SyncManager::ReceivedExperiment(browser_sync::Experiments* experiments)
     const {
   ReadTransaction trans(FROM_HERE, GetUserShare());
   ReadNode node(&trans);
@@ -2486,11 +2487,16 @@ bool SyncManager::ReceivedExperimentalTypes(syncable::ModelTypeSet* to_add)
     DVLOG(1) << "Couldn't find Nigori node.";
     return false;
   }
+  bool found_experiment = false;
   if (node.GetNigoriSpecifics().sync_tabs()) {
-    to_add->Put(syncable::SESSIONS);
-    return true;
+    experiments->sync_tabs = true;
+    found_experiment = true;
+  }
+  if (node.GetNigoriSpecifics().sync_tab_favicons()) {
+    experiments->sync_tab_favicons = true;
+    found_experiment = true;
   }
-  return false;
+  return found_experiment;
 }
 
 bool SyncManager::HasUnsyncedItems() const {
diff --git a/sync/internal_api/sync_manager.h b/sync/internal_api/sync_manager.h
index 8288164..cfc05a0 100644
--- a/sync/internal_api/sync_manager.h
+++ b/sync/internal_api/sync_manager.h
@@ -25,6 +25,7 @@
 
 namespace browser_sync {
 class Encryptor;
+struct Experiments;
 class ExtensionsActivityMonitor;
 class JsBackend;
 class JsEventHandler;
@@ -591,10 +592,10 @@ class SyncManager {
   // Note: opens a transaction.  May be called from any thread.
   syncable::ModelTypeSet GetEncryptedDataTypesForTest() const;
 
-  // Reads the nigori node to determine if any experimental types should be
-  // enabled.
+  // Reads the nigori node to determine if any experimental features should
+  // be enabled.
   // Note: opens a transaction.  May be called on any thread.
-  bool ReceivedExperimentalTypes(syncable::ModelTypeSet* to_add) const;
+  bool ReceivedExperiment(browser_sync::Experiments* experiments) const;
 
   // Uses a read-only transaction to determine if the directory being synced has
   // any remaining unsynced items.  May be called on any thread.