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

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index cdb23b4655d6b2caadde4a9bd16f45d99902e4fd..330574cc82f0f10615d6913f700e3279980c9bde 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -18,6 +18,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <vector>
 
 #include "v8-version.h"
 #include "v8config.h"
@@ -77,6 +78,7 @@ class External;
 class Function;
 class FunctionTemplate;
 class HeapProfiler;
+class HeapSpacesStatistics;
 class ImplementationUtilities;
 class Int32;
 class Integer;
@@ -4877,18 +4879,42 @@ typedef void (*InterruptCallback)(Isolate* isolate, void* data);
 class V8_EXPORT HeapStatistics {
  public:
   HeapStatistics();
+  ~HeapStatistics();
+
+  class SpaceStatistics {
+   public:
+    SpaceStatistics(const char* name,
+                    size_t size,
+                    size_t used_size,
+                    size_t available_size,
+                    size_t physical_size)
+        : space_name(name),
+          space_size(size),
+          space_used_size(used_size),
+          space_avalable_size(available_size),
+          physical_space_size(physical_size) {}
+    const char* space_name;
+    size_t space_size;
+    size_t space_used_size;
+    size_t space_avalable_size;
+    size_t physical_space_size;
+  };
+
   size_t total_heap_size() { return total_heap_size_; }
   size_t total_heap_size_executable() { return total_heap_size_executable_; }
   size_t total_physical_size() { return total_physical_size_; }
   size_t used_heap_size() { return used_heap_size_; }
   size_t heap_size_limit() { return heap_size_limit_; }
 
+  std::vector<SpaceStatistics>* SpacesStatistics();
+
  private:
   size_t total_heap_size_;
   size_t total_heap_size_executable_;
   size_t total_physical_size_;
   size_t used_heap_size_;
   size_t heap_size_limit_;
+  HeapSpacesStatistics* spaces_statistics_;
 
   friend class V8;
   friend class Isolate;