[USS] Show USS counters in about:sync page

components/sync/driver/sync_service.h

 // Copyright 2015 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.
 
 #ifndef COMPONENTS_SYNC_DRIVER_SYNC_SERVICE_H_
 #define COMPONENTS_SYNC_DRIVER_SYNC_SERVICE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 290 matching lines @@
   //
   // The format is:
   // [ {"name": <name>, "value": <value>, "status": <status> }, ... ]
   // where <name> is a type's name, <value> is a string providing details for
   // the type's status, and <status> is one of "error", "warning" or "ok"
   // depending on the type's current status.
   //
   // This function is used by about_sync_util.cc to help populate the about:sync
   // page.  It returns a ListValue rather than a DictionaryValue in part to make
   // it easier to iterate over its elements when constructing that page.
-  virtual base::Value* GetTypeStatusMap() const = 0;
+  virtual base::Value* GetTypeStatusMap() = 0;
 
   virtual const GURL& sync_service_url() const = 0;
 
   virtual std::string unrecoverable_error_message() const = 0;
   virtual tracked_objects::Location unrecoverable_error_location() const = 0;
 
   virtual void AddProtocolEventObserver(
       browser_sync::ProtocolEventObserver* observer) = 0;
   virtual void RemoveProtocolEventObserver(
       browser_sync::ProtocolEventObserver* observer) = 0;
@@ skipping 19 matching lines @@
  protected:
   SyncService() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SyncService);
 };
 
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_SYNC_SERVICE_H_