Use TracedValue in runtime statistics.

src/counters.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COUNTERS_H_
 #define V8_COUNTERS_H_
 
 #include "include/v8.h"
 #include "src/allocation.h"
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/time.h"
 #include "src/builtins/builtins.h"
 #include "src/globals.h"
 #include "src/isolate.h"
 #include "src/objects.h"
 #include "src/runtime/runtime.h"
 #include "src/tracing/trace-event.h"
+#include "src/tracing/traced-value.h"
 
 namespace v8 {
 namespace internal {
 
 // StatsCounters is an interface for plugging into external
 // counters for monitoring.  Counters can be looked up and
 // manipulated by name.
 
 class StatsTable {
  public:
@@ skipping 449 matching lines @@
   // The aggregate_value_ is the average for [start_ms_; last_ms_].
   // The value is the average for [last_ms_; current_ms].
   // Return the weighted average of the aggregate_value_ and the value.
   return aggregate_value_ * ((last_ms_ - start_ms_) / interval_ms) +
          value * ((current_ms - last_ms_) / interval_ms);
 }
 
 struct RuntimeCallCounter {
   explicit RuntimeCallCounter(const char* name) : name(name) {}
   V8_NOINLINE void Reset();
-  V8_NOINLINE void Dump(std::stringstream& out);
+  V8_NOINLINE void Dump(v8::tracing::TracedValue* value);
 
   const char* name;
   int64_t count = 0;
   base::TimeDelta time;
 };
 
 // RuntimeCallTimer is used to keep track of the stack of currently active
 // timers used for properly measuring the own time of a RuntimeCallCounter.
 class RuntimeCallTimer {
  public:
@@ skipping 294 matching lines @@
   // parent.
   static void Leave(RuntimeCallStats* stats, RuntimeCallTimer* timer);
 
   // Set counter id for the innermost measurement. It can be used to refine
   // event kind when a runtime entry counter is too generic.
   static void CorrectCurrentCounterId(RuntimeCallStats* stats,
                                       CounterId counter_id);
 
   void Reset();
   void Print(std::ostream& os);
-  std::string Dump();
+  V8_NOINLINE void Dump(v8::tracing::TracedValue* value);
 
   RuntimeCallStats() {
     Reset();
     in_use_ = false;
   }
 
   RuntimeCallTimer* current_timer() { return current_timer_; }
   bool InUse() { return in_use_; }
 
  private:
-  std::stringstream buffer_;
   // Counter to track recursive time events.
   RuntimeCallTimer* current_timer_ = NULL;
   // Used to track nested tracing scopes.
   bool in_use_;
 };
 
 #define TRACE_RUNTIME_CALL_STATS(isolate, counter_name)                 \
   do {                                                                  \
     if (V8_UNLIKELY(TRACE_EVENT_RUNTIME_CALL_STATS_TRACING_ENABLED() || \
                     FLAG_runtime_call_stats)) {                         \
@@ skipping 448 matching lines @@
   }
 
   Isolate* isolate_ = nullptr;
   RuntimeCallTimer timer_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COUNTERS_H_