Add comment why SummaryStatSp isn't forward declared

Author: Jlalond

lldb/include/lldb/Target/Statistics.h

@@ -182,8 +182,7 @@ struct StatisticsOptions {
 class SummaryStatistics {
 public:
   explicit SummaryStatistics(std::string name, std::string impl_type)
-      : m_total_time(), m_impl_type(std::move(impl_type)),
-        m_name(std::move(name)), m_count(0) {}
+      : m_total_time(), m_impl_type(std::move(impl_type)), m_name(std::move(name)), m_count(0) {}
 
   std::string GetName() const { return m_name; };
   double GetTotalTime() const { return m_total_time.get().count(); }
@@ -226,6 +225,7 @@ class SummaryStatistics {
   std::atomic<uint64_t> m_count;
 };
 
+// Declaring here as there is no private forward
 typedef std::shared_ptr<SummaryStatistics> SummaryStatisticsSP;
 
 /// A class that wraps a std::map of SummaryStatistics objects behind a mutex.
@@ -237,7 +237,7 @@ class SummaryStatisticsCache {
   GetSummaryStatisticsForProvider(lldb_private::TypeSummaryImpl &provider) {
     std::lock_guard<std::mutex> guard(m_map_mutex);
     if (auto iterator = m_summary_stats_map.find(provider.GetName());
-        iterator != m_summary_stats_map.end())
+         iterator != m_summary_stats_map.end())
       return iterator->second;
 
     auto it = m_summary_stats_map.try_emplace(