[debug,api] Do not use embedder field for debug context id.

src/inspector/inspected-context.cc

Index: src/inspector/inspected-context.cc
diff --git a/src/inspector/inspected-context.cc b/src/inspector/inspected-context.cc
index 0509683789d6762e9ff865d49f02eaf235238958..8a87a12ecf16c18de973efe5b0779cab0e8a2a6a 100644
--- a/src/inspector/inspected-context.cc
+++ b/src/inspector/inspected-context.cc
@@ -4,6 +4,7 @@
 
 #include "src/inspector/inspected-context.h"
 
+#include "src/debug/debug-interface.h"
 #include "src/inspector/injected-script.h"
 #include "src/inspector/string-util.h"
 #include "src/inspector/v8-console.h"
@@ -25,8 +26,7 @@ InspectedContext::InspectedContext(V8InspectorImpl* inspector,
       m_auxData(toString16(info.auxData)),
       m_reported(false) {
   v8::Isolate* isolate = m_inspector->isolate();
-  info.context->SetEmbedderData(static_cast<int>(v8::Context::kDebugIdIndex),
-                                v8::Int32::New(isolate, contextId));
+  v8::debug::SetContextId(info.context, contextId);
   v8::Local<v8::Object> global = info.context->Global();
   v8::Local<v8::Object> console =
       m_inspector->console()->createConsole(info.context);
@@ -46,10 +46,7 @@ InspectedContext::~InspectedContext() {
 
 // static
 int InspectedContext::contextId(v8::Local<v8::Context> context) {
-  v8::Local<v8::Value> data =
-      context->GetEmbedderData(static_cast<int>(v8::Context::kDebugIdIndex));
-  if (data.IsEmpty() || !data->IsInt32()) return 0;
-  return static_cast<int>(data.As<v8::Int32>()->Value());
+  return v8::debug::GetContextId(context);
 }
 
 v8::Local<v8::Context> InspectedContext::context() const {