[USS] Show USS counters in about:sync page

components/browser_sync/profile_sync_service.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 "components/browser_sync/profile_sync_service.h"
 
 #include <stddef.h>
 
 #include <cstddef>
 #include <map>
@@ skipping 538 matching lines @@
                     OnCommitCountersUpdated(type, counters));
 }
 
 void ProfileSyncService::OnDirectoryTypeUpdateCounterUpdated(
     syncer::ModelType type,
     const syncer::UpdateCounters& counters) {
   FOR_EACH_OBSERVER(syncer::TypeDebugInfoObserver, type_debug_info_observers_,
                     OnUpdateCountersUpdated(type, counters));
 }
 
-void ProfileSyncService::OnDirectoryTypeStatusCounterUpdated(
+void ProfileSyncService::OnDatatypeStatusCounterUpdated(
     syncer::ModelType type,
-    const syncer::StatusCounters& counters) {
+    std::unique_ptr<syncer::StatusCounters> counters) {
   FOR_EACH_OBSERVER(syncer::TypeDebugInfoObserver, type_debug_info_observers_,
-                    OnStatusCountersUpdated(type, counters));
+                    OnStatusCountersUpdated(type, std::move(counters)));

[pavely, 2016/09/30 00:01:51]

This macro expands into a loop with function invocation included in it. With
multiple observers I think only one will get ownership of counters.

Why do you need to transfer ownership?

[Gang Wu, 2016/10/01 07:14:09]

my bad, will update.

 }
 
 void ProfileSyncService::OnDataTypeRequestsSyncStartup(syncer::ModelType type) {
   DCHECK(syncer::UserTypes().Has(type));
 
   if (!GetPreferredDataTypes().Has(type)) {
     // We can get here as datatype SyncableServices are typically wired up
     // to the native datatype even if sync isn't enabled.
     DVLOG(1) << "Dropping sync startup request because type "
              << syncer::ModelTypeToString(type) << "not enabled.";
@@ skipping 1240 matching lines @@
 
 void ProfileSyncService::GetModelSafeRoutingInfo(
     syncer::ModelSafeRoutingInfo* out) const {
   if (backend_.get() && backend_initialized_) {
     backend_->GetModelSafeRoutingInfo(out);
   } else {
     NOTREACHED();
   }
 }
 
-base::Value* ProfileSyncService::GetTypeStatusMap() const {
+base::Value* ProfileSyncService::GetTypeStatusMap() {
   std::unique_ptr<base::ListValue> result(new base::ListValue());
 
   if (!backend_.get() || !backend_initialized_) {
     return result.release();
   }
 
   DataTypeStatusTable::TypeErrorMap error_map =
       data_type_status_table_.GetAllErrors();
   ModelTypeSet active_types;
   ModelTypeSet passive_types;
@@ skipping 62 matching lines @@
       type_status->SetString("value", "Throttled");
     } else if (active_types.Has(type)) {
       type_status->SetString("status", "ok");
       type_status->SetString(
           "value", "Active: " + ModelSafeGroupToString(routing_info[type]));
     } else {
       type_status->SetString("status", "warning");
       type_status->SetString("value", "Disabled by User");
     }
 
-    int live_count = detailed_status.num_entries_by_type[type] -
-                     detailed_status.num_to_delete_entries_by_type[type];
-    type_status->SetInteger("num_entries",
-                            detailed_status.num_entries_by_type[type]);
-    type_status->SetInteger("num_live", live_count);
+    const auto& dtc_iter = data_type_controllers_.find(type);
+    if (dtc_iter != data_type_controllers_.end()) {
+      dtc_iter->second->GetStatusCounters(
+          base::Bind(&ProfileSyncService::OnDatatypeStatusCounterUpdated,
+                     base::Unretained(this)));
+    }
 
     result->Append(std::move(type_status));
   }
   return result.release();
 }
 
 void ProfileSyncService::ConsumeCachedPassphraseIfPossible() {
   // If no cached passphrase, or sync backend hasn't started up yet, just exit.
   // If the backend isn't running yet, OnBackendInitialized() will call this
   // method again after the backend starts up.
@@ skipping 581 matching lines @@
   if (--outstanding_setup_in_progress_handles_ != 0)
     return;
 
   DCHECK(startup_controller_->IsSetupInProgress());
   startup_controller_->SetSetupInProgress(false);
 
   if (IsBackendInitialized())
     ReconfigureDatatypeManager();
   NotifyObservers();
 }