Move browsing_data counter sync tests to separate file

components/browsing_data/core/counters/browsing_data_counter.h

Index: components/browsing_data/core/counters/browsing_data_counter.h
diff --git a/components/browsing_data/core/counters/browsing_data_counter.h b/components/browsing_data/core/counters/browsing_data_counter.h
index d7d532ae0346cee91a594c6248d1139a29ba0ab8..a6cb28804d00c81d4abf3a035d11b1d871249c01 100644
--- a/components/browsing_data/core/counters/browsing_data_counter.h
+++ b/components/browsing_data/core/counters/browsing_data_counter.h
@@ -60,6 +60,23 @@ class BrowsingDataCounter {
     DISALLOW_COPY_AND_ASSIGN(FinishedResult);
   };
 
+  // A subclass of FinishedResult that besides |Value()| also stores whether
+  // the datatype is synced.
+  class SyncResult : public FinishedResult {
+   public:
+    SyncResult(const BrowsingDataCounter* source,
+               ResultInt value,
+               bool sync_enabled);
+    ~SyncResult() override;
+
+    bool is_sync_enabled() const { return sync_enabled_; }
+
+   private:
+    bool sync_enabled_;
+
+    DISALLOW_COPY_AND_ASSIGN(SyncResult);
+  };
+
   typedef base::Callback<void(std::unique_ptr<Result>)> Callback;
 
   // Every calculation progresses through a state machine. At initialization,