Reland of [counters] adding runtime call timers for GC

src/heap/gc-tracer.h

 // Copyright 2014 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_HEAP_GC_TRACER_H_
 #define V8_HEAP_GC_TRACER_H_
 
 #include "src/base/platform/platform.h"
+#include "src/counters.h"
 #include "src/globals.h"
 
 namespace v8 {
 namespace internal {
 
 // A simple ring buffer class with maximum size known at compile time.
 // The class only implements the functionality required in GCTracer.
 template <typename T, size_t MAX_SIZE>
 class RingBuffer {
  public:
@@ skipping 62 matching lines @@
   T elements_[MAX_SIZE + 1];
   size_t begin_;
   size_t end_;
 
   DISALLOW_COPY_AND_ASSIGN(RingBuffer);
 };
 
 
 enum ScavengeSpeedMode { kForAllObjects, kForSurvivedObjects };
 
-
 // GCTracer collects and prints ONE line after each garbage collector
 // invocation IFF --trace_gc is used.
 // TODO(ernstm): Unit tests.
 class GCTracer {
  public:
   class Scope {
    public:
     enum ScopeId {
       EXTERNAL_WEAK_GLOBAL_HANDLES,
       MC_CLEAR,
@@ skipping 43 matching lines @@
       NUMBER_OF_SCOPES
     };
 
     Scope(GCTracer* tracer, ScopeId scope);
     ~Scope();
 
    private:
     GCTracer* tracer_;
     ScopeId scope_;
     double start_time_;
+    RuntimeCallTimer timer_;
 
     DISALLOW_COPY_AND_ASSIGN(Scope);
   };
 
 
   class AllocationEvent {
    public:
     // Default constructor leaves the event uninitialized.
     AllocationEvent() {}
 
@@ skipping 441 matching lines @@
   // Accumulated duration and allocated bytes since the last GC.
   double allocation_duration_since_gc_;
   size_t new_space_allocation_in_bytes_since_gc_;
   size_t old_generation_allocation_in_bytes_since_gc_;
 
   double combined_mark_compact_speed_cache_;
 
   // Counts how many tracers were started without stopping.
   int start_counter_;
 
+  // Separate timer used for --runtime_call_stats
+  RuntimeCallTimer timer_;
+
   DISALLOW_COPY_AND_ASSIGN(GCTracer);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_GC_TRACER_H_