[api] Add an API function to set the GetExternallyAllocatedMemoryInBytesCallback.

src/api.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/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 8208 matching lines @@
   i::Isolate* isolate = i::Isolate::Current();
   isolate->heap()->AddGCEpilogueCallback(
       reinterpret_cast<v8::Isolate::GCCallback>(callback), gc_type, false);
 }
 
 void Isolate::SetEmbedderHeapTracer(EmbedderHeapTracer* tracer) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->heap()->SetEmbedderHeapTracer(tracer);
 }
 
+void Isolate::SetGetExternallyAllocatedMemoryInBytesCallback(
+    GetExternallyAllocatedMemoryInBytesCallback callback) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
+  isolate->heap()->SetGetExternallyAllocatedMemoryInBytesCallback(callback);
+}
+
 void Isolate::TerminateExecution() {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->stack_guard()->RequestTerminateExecution();
 }
 
 
 bool Isolate::IsExecutionTerminating() {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   return IsExecutionTerminatingCheck(isolate);
 }
@@ skipping 2225 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8