Revert "Revert 182527" ([Sync] Make SESSIONS an implicit type)

Win_aura compile failure seems like bot flakiness

Original codereview at https://codereview.chromium.org/11961030/

TBR=tim@chromium.org,jhawkins@chromium.org
BUG=170162


Review URL: https://chromiumcodereview.appspot.com/12286007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@185743 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 50 insertions, 12 deletions

diff --git a/sync/internal_api/public/base/model_type.h b/sync/internal_api/public/base/model_type.h
index 4b9e721..a44ad19 100644
--- a/sync/internal_api/public/base/model_type.h
+++ b/sync/internal_api/public/base/model_type.h
@@ -49,6 +49,11 @@ enum ModelType {
   // can be represented in the protocol using a specific Message type in the
   // EntitySpecifics protocol buffer.
   //
+  // WARNING: Modifying the order of these types or inserting a new type above
+  // these will affect numerous histograms that rely on the enum values being
+  // consistent. When adding a new type, add it to the end of the user model
+  // types section, but before the proxy types.
+  //
   // A bookmark folder or a bookmark URL object.
   BOOKMARKS,
   FIRST_USER_MODEL_TYPE = BOOKMARKS,  // Declared 2nd, for debugger prettiness.
@@ -90,8 +95,22 @@ enum ModelType {
   FAVICON_IMAGES,
   // Favicon tracking information.
   FAVICON_TRACKING,
-  LAST_USER_MODEL_TYPE = FAVICON_TRACKING,
 
+  // ---- Proxy types ----
+  // Proxy types are excluded from the sync protocol, but are still considered
+  // real user types. By convention, we prefix them with 'PROXY_' to distinguish
+  // them from normal protocol types.
+
+  // Tab sync. This is a placeholder type, so that Sessions can be implicitly
+  // enabled for history sync and tabs sync.
+  PROXY_TABS,
+
+  FIRST_PROXY_TYPE = PROXY_TABS,
+  LAST_PROXY_TYPE = PROXY_TABS,
+
+  LAST_USER_MODEL_TYPE = PROXY_TABS,
+
+  // ---- Control Types ----
   // An object representing a set of Nigori keys.
   NIGORI,
   FIRST_CONTROL_MODEL_TYPE = NIGORI,
diff --git a/sync/protocol/proto_value_conversions.cc b/sync/protocol/proto_value_conversions.cc
index 3964578..bc5b0ae 100644
--- a/sync/protocol/proto_value_conversions.cc
+++ b/sync/protocol/proto_value_conversions.cc
@@ -620,6 +620,7 @@ base::DictionaryValue* GetUpdatesMessageToValue(
   SET_INT32(batch_size);
   SET_REP(from_progress_marker, DataTypeProgressMarkerToValue);
   SET_BOOL(streaming);
+  SET_BOOL(need_encryption_key);
   SET_BOOL(create_mobile_bookmarks_folder);
   return value;
 }
@@ -777,6 +778,7 @@ base::DictionaryValue* ClientConfigParamsToValue(
     const sync_pb::ClientConfigParams& proto) {
   base::DictionaryValue* value = new base::DictionaryValue();
   SET_INT32_REP(enabled_type_ids);
+  SET_BOOL(tabs_datatype_enabled);
   return value;
 }
 
diff --git a/sync/protocol/proto_value_conversions_unittest.cc b/sync/protocol/proto_value_conversions_unittest.cc
index b82045a..6258fa6 100644
--- a/sync/protocol/proto_value_conversions_unittest.cc
+++ b/sync/protocol/proto_value_conversions_unittest.cc
@@ -52,7 +52,7 @@ TEST_F(ProtoValueConversionsTest, ProtoChangeCheck) {
   // If this number changes, that means we added or removed a data
   // type.  Don't forget to add a unit test for {New
   // type}SpecificsToValue below.
-  EXPECT_EQ(25, MODEL_TYPE_COUNT);
+  EXPECT_EQ(26, MODEL_TYPE_COUNT);
 
   // We'd also like to check if we changed any field in our messages.
   // However, that's hard to do: sizeof could work, but it's
@@ -244,7 +244,8 @@ TEST_F(ProtoValueConversionsTest, EntitySpecificsToValue) {
 #undef SET_FIELD
 
   scoped_ptr<DictionaryValue> value(EntitySpecificsToValue(specifics));
-  EXPECT_EQ(MODEL_TYPE_COUNT - FIRST_REAL_MODEL_TYPE,
+  EXPECT_EQ(MODEL_TYPE_COUNT - FIRST_REAL_MODEL_TYPE -
+            (LAST_PROXY_TYPE - FIRST_PROXY_TYPE + 1),
             static_cast<int>(value->size()));
 }
 
diff --git a/sync/protocol/sync.proto b/sync/protocol/sync.proto
index 934021d..37e4455 100644
--- a/sync/protocol/sync.proto
+++ b/sync/protocol/sync.proto
@@ -370,8 +370,13 @@ message ChromiumExtensionsActivity {
 
 // Client specific configuration information.
 message ClientConfigParams {
-  // The set of data types this client has enabled.
+  // The set of data types this client has enabled. Note that this does not
+  // include proxy types, as they do not have protocol field numbers and are
+  // placeholder types that implicitly enable protocol types.
  repeated int32 enabled_type_ids = 1;
+
+ // Whether the PROXY_TABS proxy datatype is enabled on this client.
+ optional bool tabs_datatype_enabled = 2;
 };
 
 message CommitMessage {
diff --git a/sync/syncable/model_type.cc b/sync/syncable/model_type.cc
index ba7a7f0..99cf1e9 100644
--- a/sync/syncable/model_type.cc
+++ b/sync/syncable/model_type.cc
@@ -329,15 +329,17 @@ ModelTypeSet UserTypes() {
 
 ModelTypeSet UserSelectableTypes() {
   ModelTypeSet set;
-  set.Put(APPS);
-  set.Put(AUTOFILL);
+  // Although the order doesn't technically matter here, it's clearer to keep
+  // these in the same order as their definition in the ModelType enum.
   set.Put(BOOKMARKS);
-  set.Put(EXTENSIONS);
+  set.Put(PREFERENCES);;
   set.Put(PASSWORDS);
-  set.Put(PREFERENCES);
-  set.Put(SESSIONS);
+  set.Put(AUTOFILL);
   set.Put(THEMES);
   set.Put(TYPED_URLS);
+  set.Put(EXTENSIONS);
+  set.Put(APPS);
+  set.Put(PROXY_TABS);
   return set;
 }
 
@@ -375,7 +377,7 @@ ModelTypeSet ControlTypes() {
 
 ModelTypeSet ProxyTypes() {
   ModelTypeSet set;
-  // TODO(zea): add a TABS type here.
+  set.Put(PROXY_TABS);
   return set;
 }
 
@@ -438,6 +440,8 @@ const char* ModelTypeToString(ModelType model_type) {
       return "Favicon Images";
     case FAVICON_TRACKING:
       return "Favicon Tracking";
+    case PROXY_TABS:
+      return "Tabs";
     default:
       break;
   }
@@ -519,6 +523,8 @@ ModelType ModelTypeFromString(const std::string& model_type_string) {
     return FAVICON_IMAGES;
   else if (model_type_string == "Favicon Tracking")
     return FAVICON_TRACKING;
+  else if (model_type_string == "Tabs")
+    return PROXY_TABS;
   else
     NOTREACHED() << "No known model type corresponding to "
                  << model_type_string << ".";
@@ -605,6 +611,8 @@ std::string ModelTypeToRootTag(ModelType type) {
       return "google_chrome_favicon_images";
     case FAVICON_TRACKING:
       return "google_chrome_favicon_tracking";
+    case PROXY_TABS:
+      return std::string();
     default:
       break;
   }
diff --git a/sync/syncable/nigori_util.cc b/sync/syncable/nigori_util.cc
index 0b6c40c..4888f66 100644
--- a/sync/syncable/nigori_util.cc
+++ b/sync/syncable/nigori_util.cc
@@ -252,7 +252,7 @@ void UpdateNigoriFromEncryptedTypes(ModelTypeSet encrypted_types,
                                     bool encrypt_everything,
                                     sync_pb::NigoriSpecifics* nigori) {
   nigori->set_encrypt_everything(encrypt_everything);
-  COMPILE_ASSERT(25 == MODEL_TYPE_COUNT, UpdateEncryptedTypes);
+  COMPILE_ASSERT(26 == MODEL_TYPE_COUNT, UpdateEncryptedTypes);
   nigori->set_encrypt_bookmarks(
       encrypted_types.Has(BOOKMARKS));
   nigori->set_encrypt_preferences(
@@ -286,7 +286,7 @@ ModelTypeSet GetEncryptedTypesFromNigori(
     return ModelTypeSet::All();
 
   ModelTypeSet encrypted_types;
-  COMPILE_ASSERT(25 == MODEL_TYPE_COUNT, UpdateEncryptedTypes);
+  COMPILE_ASSERT(26 == MODEL_TYPE_COUNT, UpdateEncryptedTypes);
   if (nigori.encrypt_bookmarks())
     encrypted_types.Put(BOOKMARKS);
   if (nigori.encrypt_preferences())
diff --git a/sync/util/data_type_histogram.h b/sync/util/data_type_histogram.h
index d3dfd73..c911ce4 100644
--- a/sync/util/data_type_histogram.h
+++ b/sync/util/data_type_histogram.h
@@ -105,6 +105,9 @@
       case ::syncer::FAVICON_TRACKING: \
         PER_DATA_TYPE_MACRO("FaviconTracking"); \
         break; \
+      case ::syncer::PROXY_TABS :\
+        PER_DATA_TYPE_MACRO("Tabs"); \
+        break; \
       default: \
         NOTREACHED() << "Unknown datatype " \
                      << ::syncer::ModelTypeToString(datatype);  \