Added a whitelist for trace events that are known to be PII-less.

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 9d8d74d6a6be387949f102dc1381d8371fdb88f0..d128d8ff58f74ac9855b9d951458b6b88a0ca524 100644
--- a/base/trace_event/trace_event_impl.h
+++ b/base/trace_event/trace_event_impl.h
@@ -387,12 +387,14 @@ struct BASE_EXPORT TraceOptions {
   TraceOptions()
       : record_mode(RECORD_UNTIL_FULL),
         enable_sampling(false),
-        enable_systrace(false) {}
+        enable_systrace(false),
+        enable_args_whitelist(false) {}
 
   explicit TraceOptions(TraceRecordMode record_mode)
       : record_mode(record_mode),
         enable_sampling(false),
-        enable_systrace(false) {}
+        enable_systrace(false),
+        enable_args_whitelist(false) {}
 
   // |options_string| is a comma-delimited list of trace options.
   // Possible options are: "record-until-full", "record-continuously",
@@ -423,6 +425,7 @@ struct BASE_EXPORT TraceOptions {
   TraceRecordMode record_mode;
   bool enable_sampling;
   bool enable_systrace;
+  bool enable_args_whitelist;
 };
 
 struct BASE_EXPORT TraceLogStatus {
@@ -753,6 +756,7 @@ class BASE_EXPORT TraceLog {
   static const InternalTraceOptions kInternalEchoToConsole;
   static const InternalTraceOptions kInternalEnableSampling;
   static const InternalTraceOptions kInternalRecordAsMuchAsPossible;
+  static const InternalTraceOptions kInternalEnableArgsWhitelist;
 
   // This lock protects TraceLog member accesses (except for members protected
   // by thread_info_lock_) from arbitrary threads.