Add heap space sizes and external memory counter to V8 statistics extension.

src/heap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1579 matching lines @@
   // Global inline caching age: it is incremented on some GCs after context
   // disposal. We use it to flush inline caches.
   int global_ic_age() {
     return global_ic_age_;
   }
 
   void AgeInlineCaches() {
     global_ic_age_ = (global_ic_age_ + 1) & SharedFunctionInfo::ICAgeBits::kMax;
   }
 
+  intptr_t amount_of_external_allocated_memory() {
+    return amount_of_external_allocated_memory_;
+  }
+
   // ObjectStats are kept in two arrays, counts and sizes. Related stats are
   // stored in a contiguous linear buffer. Stats groups are stored one after
   // another.
   enum {
     FIRST_CODE_KIND_SUB_TYPE = LAST_TYPE + 1,
     FIRST_FIXED_ARRAY_SUB_TYPE =
         FIRST_CODE_KIND_SUB_TYPE + Code::LAST_CODE_KIND + 1,
     OBJECT_STATS_COUNT =
         FIRST_FIXED_ARRAY_SUB_TYPE + LAST_FIXED_ARRAY_SUB_TYPE + 1
   };
@@ skipping 1158 matching lines @@
   AssertNoAllocation no_alloc;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_