[heap] Introduce enum of garbage collection reasons.

src/extensions/statistics-extension.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/extensions/statistics-extension.h"
 
 #include "src/counters.h"
 #include "src/heap/heap-inl.h"
 #include "src/isolate.h"
 
@@ skipping 49 matching lines @@
 void StatisticsExtension::GetCounters(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   Isolate* isolate = reinterpret_cast<Isolate*>(args.GetIsolate());
   Heap* heap = isolate->heap();
 
   if (args.Length() > 0) {  // GC if first argument evaluates to true.
     if (args[0]->IsBoolean() &&
         args[0]
             ->BooleanValue(args.GetIsolate()->GetCurrentContext())
             .FromMaybe(false)) {
-      heap->CollectAllGarbage(Heap::kNoGCFlags, "counters extension");
+      heap->CollectAllGarbage(Heap::kNoGCFlags,
+                              GarbageCollectionReason::kCountersExtension);
     }
   }
 
   Counters* counters = isolate->counters();
   v8::Local<v8::Object> result = v8::Object::New(args.GetIsolate());
 
   struct StatisticsCounter {
     v8::internal::StatsCounter* counter;
     const char* name;
   };
@@ skipping 77 matching lines @@
   }
 
   AddNumber(args.GetIsolate(), result, reloc_info_total,
             "reloc_info_total_size");
   AddNumber(args.GetIsolate(), result, source_position_table_total,
             "source_position_table_total_size");
 }
 
 }  // namespace internal
 }  // namespace v8