Sync cleanup: Remove Experiments::gcm_invalidations_enabled

It's always true.

Bug: 904782
Change-Id: I6cb979f5e168a33d100b3dfda00257f5d72438b5
Reviewed-on: https://chromium-review.googlesource.com/c/1341533Reviewed-by: Tatiana Gornak <melandory@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609242}

components/browser_sync/profile_sync_service.cc

@@ -1060,8 +1060,7 @@ void ProfileSyncService::OnExperimentsChanged(
   current_experiments_ = experiments;
 
   sync_client_->GetPrefService()->SetBoolean(
-      invalidation::prefs::kInvalidationServiceUseGCMChannel,
-      experiments.gcm_invalidations_enabled);
+      invalidation::prefs::kInvalidationServiceUseGCMChannel, true);
 }
 
 void ProfileSyncService::OnConnectionStatusChange(

components/invalidation/impl/invalidation_prefs.cc

@@ -19,7 +19,8 @@ const char kInvalidatorInvalidationState[] = "invalidator.invalidation_state";
 const char kInvalidatorSavedInvalidations[] = "invalidator.saved_invalidations";
 
 // Boolean indicating that TiclInvalidationService should use GCM channel.
-// False or lack of settings means XMPPPushClient channel.
+// False means XMPPPushClient channel.
+// TODO(crbug.com/904782): Get rid of this; it's always true.
 const char kInvalidationServiceUseGCMChannel[] =
     "invalidation_service.use_gcm_channel";
 

components/sync/base/experiments.h

@@ -13,25 +13,17 @@ namespace syncer {
 
 const char kFaviconSyncTag[] = "favicon_sync";
 const char kPreCommitUpdateAvoidanceTag[] = "pre_commit_update_avoidance";
-const char kGCMInvalidationsTag[] = "gcm_invalidations";
 
 // A structure to hold the enable status of experimental sync features.
 struct Experiments {
-  Experiments()
-      : favicon_sync_limit(200),
-        // By default GCM channel is enabled:
-        gcm_invalidations_enabled(true) {}
+  Experiments() : favicon_sync_limit(200) {}
 
   bool Matches(const Experiments& rhs) {
-    return (favicon_sync_limit == rhs.favicon_sync_limit &&
-            gcm_invalidations_enabled == rhs.gcm_invalidations_enabled);
+    return favicon_sync_limit == rhs.favicon_sync_limit;
   }
 
   // The number of favicons that a client is permitted to sync.
   int favicon_sync_limit;
-
-  // Enable invalidations over GCM channel.
-  bool gcm_invalidations_enabled;
 };
 
 }  // namespace syncer

components/sync/engine_impl/sync_manager_impl.cc

@@ -925,17 +925,6 @@ bool SyncManagerImpl::ReceivedExperiment(Experiments* experiments) {
     // know about this.
   }
 
-  ReadNode gcm_invalidations_node(&trans);
-  if (gcm_invalidations_node.InitByClientTagLookup(
-          EXPERIMENTS, 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;
 }
 

components/sync/protocol/experiments_specifics.proto

@@ -74,6 +74,7 @@ message ExperimentsSpecifics {
   optional GcmChannelFlags gcm_channel = 6;
   // No longer used as of M43.
   optional EnhancedBookmarksFlags obsolete_enhanced_bookmarks = 7;
+  // No longer used as of M72.
   optional GcmInvalidationsFlags gcm_invalidations = 8;
   // No longer used as of M51.
   optional WalletSyncFlags obsolete_wallet_sync = 9;