[heap] Introduce enum of garbage collection reasons.

src/objects.cc

 // Copyright 2015 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 18107 matching lines @@
     table->Rehash(isolate->factory()->undefined_value());
   }
   // If we're out of luck, we didn't get a GC recently, and so rehashing
   // isn't enough to avoid a crash.
   if (!table->HasSufficientCapacityToAdd(1)) {
     int nof = table->NumberOfElements() + 1;
     int capacity = ObjectHashTable::ComputeCapacity(nof * 2);
     if (capacity > ObjectHashTable::kMaxCapacity) {
       for (size_t i = 0; i < 2; ++i) {
         isolate->heap()->CollectAllGarbage(
-            Heap::kFinalizeIncrementalMarkingMask, "full object hash table");
+            Heap::kFinalizeIncrementalMarkingMask,
+            GarbageCollectionReason::kFullHashtable);
       }
       table->Rehash(isolate->factory()->undefined_value());
     }
   }
 
   // Check whether the hash table should be extended.
   table = EnsureCapacity(table, 1, key);
   table->AddEntry(table->FindInsertionEntry(hash), *key, *value);
   return table;
 }
@@ skipping 1278 matching lines @@
   for (PrototypeIterator iter(isolate, this, kStartAtReceiver,
                               PrototypeIterator::END_AT_NULL);
        !iter.IsAtEnd(); iter.AdvanceIgnoringProxies()) {
     if (iter.GetCurrent<Object>()->IsJSProxy()) return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8