Expose a lower bound of malloc'd memory via heap statistics

src/handles.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/handles.h"
 
 #include "src/address-map.h"
 #include "src/base/logging.h"
 #include "src/identity-map.h"
 #include "src/objects-inl.h"
@@ skipping 100 matching lines @@
 
 Address HandleScope::current_next_address(Isolate* isolate) {
   return reinterpret_cast<Address>(&isolate->handle_scope_data()->next);
 }
 
 
 Address HandleScope::current_limit_address(Isolate* isolate) {
   return reinterpret_cast<Address>(&isolate->handle_scope_data()->limit);
 }
 
-
 CanonicalHandleScope::CanonicalHandleScope(Isolate* isolate)
-    : isolate_(isolate) {
+    : isolate_(isolate), zone_(isolate->allocator()) {
   HandleScopeData* handle_scope_data = isolate_->handle_scope_data();
   prev_canonical_scope_ = handle_scope_data->canonical_scope;
   handle_scope_data->canonical_scope = this;
   root_index_map_ = new RootIndexMap(isolate);
   identity_map_ = new IdentityMap<Object**>(isolate->heap(), &zone_);
   canonical_level_ = handle_scope_data->level;
 }
 
 
 CanonicalHandleScope::~CanonicalHandleScope() {
@@ skipping 60 matching lines @@
   data->next = prev_next_;
   data->limit = prev_limit_;
 #ifdef DEBUG
   handles_detached_ = true;
 #endif
   return deferred;
 }
 
 }  // namespace internal
 }  // namespace v8