Control invalidations network channel from syncer experiment

- Created new experiment protobuf.
- ProfileSyncService writes value to prefs
- TiclInvalidationService registers for changes to both gcm
enabled and invalidations over GCM pref settings. When prefs
change it decides which channel to use and restarts
invalidator if needed.

BUG=325020
R=zea@chromium.org

Review URL: https://codereview.chromium.org/205333003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@258689 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 27 insertions, 2 deletions

diff --git a/sync/internal_api/public/util/experiments.h b/sync/internal_api/public/util/experiments.h
index 18a0887..9063cbb 100644
--- a/sync/internal_api/public/util/experiments.h
+++ b/sync/internal_api/public/util/experiments.h
@@ -15,6 +15,7 @@ const char kFaviconSyncTag[] = "favicon_sync";
 const char kPreCommitUpdateAvoidanceTag[] = "pre_commit_update_avoidance";
 const char kGCMChannelTag[] = "gcm_channel";
 const char kEnhancedBookmarksTag[] = "enhanced_bookmarks";
+const char kGCMInvalidationsTag[] = "gcm_invalidations";
 
 // A structure to hold the enable status of experimental sync features.
 struct Experiments {
@@ -27,13 +28,15 @@ struct Experiments {
   Experiments()
       : favicon_sync_limit(200),
         gcm_channel_state(UNSET),
-        enhanced_bookmarks_enabled(false) {}
+        enhanced_bookmarks_enabled(false),
+        gcm_invalidations_enabled(false) {}
 
   bool Matches(const Experiments& rhs) {
     return (favicon_sync_limit == rhs.favicon_sync_limit &&
             gcm_channel_state == rhs.gcm_channel_state &&
             enhanced_bookmarks_enabled == rhs.enhanced_bookmarks_enabled &&
-            enhanced_bookmarks_ext_id == rhs.enhanced_bookmarks_ext_id);
+            enhanced_bookmarks_ext_id == rhs.enhanced_bookmarks_ext_id &&
+            gcm_invalidations_enabled == rhs.gcm_invalidations_enabled);
   }
 
   // The number of favicons that a client is permitted to sync.
@@ -45,6 +48,9 @@ struct Experiments {
   // Enable the enhanced bookmarks sync datatype.
   bool enhanced_bookmarks_enabled;
 
+  // Enable invalidations over GCM channel.
+  bool gcm_invalidations_enabled;
+
   // Enhanced bookmarks extension id.
   std::string enhanced_bookmarks_ext_id;
 };
diff --git a/sync/internal_api/sync_manager_impl.cc b/sync/internal_api/sync_manager_impl.cc
index 8ecb29f..3b4a1fd 100644
--- a/sync/internal_api/sync_manager_impl.cc
+++ b/sync/internal_api/sync_manager_impl.cc
@@ -1129,6 +1129,18 @@ bool SyncManagerImpl::ReceivedExperiment(Experiments* experiments) {
     found_experiment = true;
   }
 
+  ReadNode gcm_invalidations_node(&trans);
+  if (gcm_invalidations_node.InitByClientTagLookup(
+          syncer::EXPERIMENTS, syncer::kGCMInvalidationsTag) ==
+      BaseNode::INIT_OK) {
+    const sync_pb::GcmInvalidationsFlags& gcm_invalidations =
+        gcm_invalidations_node.GetExperimentsSpecifics().gcm_invalidations();
+    if (gcm_invalidations.has_enabled()) {
+      experiments->gcm_invalidations_enabled = gcm_invalidations.enabled();
+      found_experiment = true;
+    }
+  }
+
   return found_experiment;
 }
 
diff --git a/sync/protocol/experiments_specifics.proto b/sync/protocol/experiments_specifics.proto
index 790cf02..723fe55 100644
--- a/sync/protocol/experiments_specifics.proto
+++ b/sync/protocol/experiments_specifics.proto
@@ -50,6 +50,11 @@ message EnhancedBookmarksFlags {
   optional string extension_id = 2;
 }
 
+// Flags for enabling GCM channel for invalidations.
+message GcmInvalidationsFlags {
+  optional bool enabled = 1;
+}
+
 // Contains one flag or set of related flags.  Each node of the experiments type
 // will have a unique_client_tag identifying which flags it contains.  By
 // convention, the tag name should match the sub-message name.
@@ -61,4 +66,5 @@ message ExperimentsSpecifics {
   optional PreCommitUpdateAvoidanceFlags pre_commit_update_avoidance = 5;
   optional GcmChannelFlags gcm_channel = 6;
   optional EnhancedBookmarksFlags enhanced_bookmarks = 7;
+  optional GcmInvalidationsFlags gcm_invalidations = 8;
 }
diff --git a/sync/protocol/proto_value_conversions.cc b/sync/protocol/proto_value_conversions.cc
index 83748faa..496a35d 100644
--- a/sync/protocol/proto_value_conversions.cc
+++ b/sync/protocol/proto_value_conversions.cc
@@ -503,6 +503,7 @@ base::DictionaryValue* ExperimentsSpecificsToValue(
   SET(favicon_sync, FaviconSyncFlagsToValue);
   SET_EXPERIMENT_ENABLED_FIELD(gcm_channel);
   SET_EXPERIMENT_ENABLED_FIELD(enhanced_bookmarks);
+  SET_EXPERIMENT_ENABLED_FIELD(gcm_invalidations);
   return value;
 }