Add reporting of JS heap size limit to GetHeapStatistics.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 883bfad9458ebc31c511ff3ba93568e2d1eab635..3a9827b24d3ba2e361c4ba326446fdd87ebee314 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -2515,6 +2515,7 @@ class V8EXPORT HeapStatistics {
   size_t total_heap_size() { return total_heap_size_; }
   size_t total_heap_size_executable() { return total_heap_size_executable_; }
   size_t used_heap_size() { return used_heap_size_; }
+  size_t heap_size_limit() { return heap_size_limit_; }
 
  private:
   void set_total_heap_size(size_t size) { total_heap_size_ = size; }
@@ -2522,10 +2523,12 @@ class V8EXPORT HeapStatistics {
     total_heap_size_executable_ = size;
   }
   void set_used_heap_size(size_t size) { used_heap_size_ = size; }
+  void set_heap_size_limit(size_t size) { heap_size_limit_ = size; }
 
   size_t total_heap_size_;
   size_t total_heap_size_executable_;
   size_t used_heap_size_;
+  size_t heap_size_limit_;
 
   friend class V8;
 };