Added a trace option for whitewashing trace args against a known-PII-less list.

base/trace_event/trace_event_impl.h

Index: base/trace_event/trace_event_impl.h
diff --git a/base/trace_event/trace_event_impl.h b/base/trace_event/trace_event_impl.h
index 33a85c9b6ce854f4e6b6cde748fe6abca8a015d2..bfbbefa0158e3b6977ceb401c0f3ed6b6d3a1e86 100644
--- a/base/trace_event/trace_event_impl.h
+++ b/base/trace_event/trace_event_impl.h
@@ -122,7 +122,10 @@ class BASE_EXPORT TraceEvent {
   void UpdateDuration(const TimeTicks& now, const TimeTicks& thread_now);
 
   // Serialize event data to JSON
-  void AppendAsJSON(std::string* out) const;
+  typedef base::Callback<bool(const char* category_group_name,
+                              const char* event_name)> EventFilterPredicate;
+  void AppendAsJSON(std::string* out,
+                    const EventFilterPredicate& event_filter_predicate) const;
   void AppendPrettyPrinted(std::ostringstream* out) const;
 
   static void AppendValueAsJSON(unsigned char type,
@@ -532,6 +535,8 @@ class BASE_EXPORT TraceLog {
   void SetEventCallbackEnabled(const CategoryFilter& category_filter,
                                EventCallback cb);
   void SetEventCallbackDisabled();
+  void SetEventFilterPredicate(
+      const TraceEvent::EventFilterPredicate& event_filter_predicate);
 
   // Flush all collected events to the given output callback. The callback will
   // be called one or more times either synchronously or asynchronously from
@@ -717,9 +722,10 @@ class BASE_EXPORT TraceLog {
   // is called for the flush of the current |logged_events_|.
   void FlushCurrentThread(int generation);
   // Usually it runs on a different thread.
-  static void ConvertTraceEventsToTraceFormat(
+  void ConvertTraceEventsToTraceFormat(
       scoped_ptr<TraceBuffer> logged_events,
-      const TraceLog::OutputCallback& flush_output_callback);
+      const TraceLog::OutputCallback& flush_output_callback,
+      const TraceEvent::EventFilterPredicate& event_filter_predicate);
   void FinishFlush(int generation);
   void OnFlushTimeout(int generation);
 
@@ -809,6 +815,7 @@ class BASE_EXPORT TraceLog {
 
   // Set when asynchronous Flush is in progress.
   OutputCallback flush_output_callback_;
+  TraceEvent::EventFilterPredicate event_filter_predicate_;
   scoped_refptr<MessageLoopProxy> flush_message_loop_proxy_;
   subtle::AtomicWord generation_;
   bool use_worker_thread_;