Adding api to get last gc object statistics for chrome://tracing.

src/heap/heap.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/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 6421 matching lines @@
       static_cast<int>(object_sizes_[index]));                                \
   counters->size_of_CODE_AGE_##name()->Decrement(                             \
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
+
+
+const char* Heap::GetObjectTypeName(size_t index) {
+  if (index > OBJECT_STATS_COUNT)
+    return nullptr;
+
+  switch (static_cast<int>(index)) {
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name) \
+  case name:                                \
+    return #name;
+    INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name)   \
+  case FIRST_CODE_KIND_SUB_TYPE + Code::name: \
+    return "CODE_TYPE_" #name;
+    CODE_KIND_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name) \
+  case FIRST_FIXED_ARRAY_SUB_TYPE + name:   \
+    return "FIXED_ARRAY_" #name;
+    FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name)                                    \
+  case FIRST_CODE_AGE_SUB_TYPE + Code::k##name##CodeAge - Code::kFirstCodeAge: \
+    return "CODE_AGE_" #name;
+    CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+  }
+  return nullptr;
+}
 }
 }  // namespace v8::internal