[heap] Add specific timer events for finalizing incremental GCs.

src/heap/heap.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_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 412 matching lines @@
   PRIVATE_SYMBOL_LIST(V)
 
 // Forward declarations.
 class ArrayBufferTracker;
 class GCIdleTimeAction;
 class GCIdleTimeHandler;
 class GCIdleTimeHeapState;
 class GCTracer;
 class HeapObjectsFilter;
 class HeapStats;
+class HistogramTimer;
 class Isolate;
 class MemoryReducer;
 class ObjectStats;
 class Scavenger;
 class ScavengeJob;
 class WeakObjectRetainer;
 
 
 // A queue of objects promoted during scavenge. Each object is accompanied
 // by it's size to avoid dereferencing a map pointer for scanning.
@@ skipping 1357 matching lines @@
 
   void AddToRingBuffer(const char* string);
   void GetFromRingBuffer(char* buffer);
 
   // Attempt to over-approximate the weak closure by marking object groups and
   // implicit references from global handles, but don't atomically complete
   // marking. If we continue to mark incrementally, we might have marked
   // objects that die later.
   void OverApproximateWeakClosure(const char* gc_reason);
 
+  // Returns the timer used for a given GC type.
+  // - GCScavenger: young generation GC
+  // - GCCompactor: full GC
+  // - GCFinalzeMC: finalization of incremental full GC
+  // - GCFinalizeMCReduceMemory: finalization of incremental full GC with
+  // memory reduction
+  HistogramTimer* GCTypeTimer(GarbageCollector collector);
+
   // ===========================================================================
   // Actual GC. ================================================================
   // ===========================================================================
 
   // Code that should be run before and after each GC.  Includes some
   // reporting/verification activities when compiled with DEBUG set.
   void GarbageCollectionPrologue();
   void GarbageCollectionEpilogue();
 
   // Performs a major collection in the whole heap.
@@ skipping 891 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_