FileWrapper[Impl] modifications and actually remove the "Impl" class.

webrtc/system_wrappers/source/trace_impl.h

Index: webrtc/system_wrappers/source/trace_impl.h
diff --git a/webrtc/system_wrappers/source/trace_impl.h b/webrtc/system_wrappers/source/trace_impl.h
index 182f5809a505d7fde3d5b078aaaca69d79f66e05..045b3cd5f58982313cc6fe47c030350f78bffceb 100644
--- a/webrtc/system_wrappers/source/trace_impl.h
+++ b/webrtc/system_wrappers/source/trace_impl.h
@@ -41,8 +41,6 @@ class TraceImpl : public Trace {
   static TraceImpl* GetTrace(const TraceLevel level = kTraceAll);
 
   int32_t SetTraceFileImpl(const char* file_name, const bool add_file_counter);
-  int32_t TraceFileImpl(char file_name[FileWrapper::kMaxFileNameSize]);
-
   int32_t SetTraceCallbackImpl(TraceCallback* callback);
 
   void AddImpl(const TraceLevel level, const TraceModule module,
@@ -82,9 +80,8 @@ class TraceImpl : public Trace {
     const TraceLevel level);
 
   bool UpdateFileName(
-    const char file_name_utf8[FileWrapper::kMaxFileNameSize],
-    char file_name_with_counter_utf8[FileWrapper::kMaxFileNameSize],
-    const uint32_t new_count) const;
+      char file_name_with_counter_utf8[FileWrapper::kMaxFileNameSize],
+      const uint32_t new_count) const EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   bool CreateFileName(
     const char file_name_utf8[FileWrapper::kMaxFileNameSize],
@@ -99,6 +96,7 @@ class TraceImpl : public Trace {
   uint32_t file_count_text_ GUARDED_BY(crit_);
 
   const std::unique_ptr<FileWrapper> trace_file_ GUARDED_BY(crit_);
+  std::string trace_file_path_ GUARDED_BY(crit_);
   rtc::CriticalSection crit_;
 };