Adding V8 api to get memory statistics of spaces in V8::Heap.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 6ee6c094bd05ebefb228697f0ca778e3b94ff906..9fd911377e1efb99566f7ad4f255f49932b34562 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -54,6 +54,14 @@
 namespace v8 {
 namespace internal {
 
+namespace {
+const char* kNewSpaceName = "new_space";
+const char* kOldSpaceName = "old_space";
+const char* kCodeSpaceName = "code_space";
+const char* kMapSpaceName = "map_space";
+const char* kLoSpaceName = "large_object_space";
+}  // namespace
+
 
 Heap::Heap()
     : amount_of_external_allocated_memory_(0),
@@ -452,6 +460,25 @@ intptr_t Heap::SizeOfObjects() {
 }
 
 
+const char* Heap::GetSpaceName(int idx) {
+  switch (idx) {
+    case NEW_SPACE:
+      return kNewSpaceName;
+    case OLD_SPACE:
+      return kOldSpaceName;
+    case MAP_SPACE:
+      return kMapSpaceName;
+    case CODE_SPACE:
+      return kCodeSpaceName;
+    case LO_SPACE:
+      return kLoSpaceName;
+    default:
+      UNREACHABLE();
+  }
+  return nullptr;
+}
+
+
 void Heap::ClearAllICsByKind(Code::Kind kind) {
   HeapObjectIterator it(code_space());