[Tracing] Embed V8 runtime call stats into tracing.

src/counters.cc

 // 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.
 
 #include "src/counters.h"
 
 #include <iomanip>
 
 #include "src/base/platform/platform.h"
 #include "src/isolate.h"
@@ skipping 255 matching lines @@
   uint64_t total_call_count = 0;
   base::TimeDelta total_time;
   std::vector<Entry> entries;
 };
 
 void RuntimeCallCounter::Reset() {
   count = 0;
   time = base::TimeDelta();
 }
 
+void RuntimeCallCounter::Dump(std::stringstream& out) {
+  out << "\"" << name << "\":[" << count << "," << time.InMicroseconds()
+      << "],";
+}
+
 // static
 void RuntimeCallStats::Enter(Isolate* isolate, RuntimeCallTimer* timer,
                              CounterId counter_id) {
   RuntimeCallStats* stats = isolate->counters()->runtime_call_stats();
   RuntimeCallCounter* counter = &(stats->*counter_id);
   timer->Start(counter, stats->current_timer_);
   stats->current_timer_ = timer;
 }
 
 // static
@@ skipping 65 matching lines @@
   FOR_EACH_API_COUNTER(RESET_COUNTER)
 #undef RESET_COUNTER
 
 #define RESET_COUNTER(name) this->Handler_##name.Reset();
   FOR_EACH_HANDLER_COUNTER(RESET_COUNTER)
 #undef RESET_COUNTER
 }
 
 }  // namespace internal
 }  // namespace v8