[inspector] Store interger in context embedder data instead of a string.

src/inspector/inspected-context.cc

 // Copyright 2016 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/inspector/inspected-context.h"
 
 #include "src/inspector/injected-script.h"
 #include "src/inspector/string-util.h"
 #include "src/inspector/v8-console.h"
 #include "src/inspector/v8-inspector-impl.h"
@@ skipping 23 matching lines @@
 InspectedContext::InspectedContext(V8InspectorImpl* inspector,
                                    const V8ContextInfo& info, int contextId)
     : m_inspector(inspector),
       m_context(info.context->GetIsolate(), info.context),
       m_contextId(contextId),
       m_contextGroupId(info.contextGroupId),
       m_origin(toString16(info.origin)),
       m_humanReadableName(toString16(info.humanReadableName)),
       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));
   m_context.SetWeak(&m_context, &clearContext,
                     v8::WeakCallbackType::kParameter);
 
-  v8::Isolate* isolate = m_inspector->isolate();
   v8::Local<v8::Object> global = info.context->Global();
   v8::Local<v8::Object> console =
       V8Console::createConsole(this, info.hasMemoryOnConsole);
   if (!global
            ->Set(info.context, toV8StringInternalized(isolate, "console"),
                  console)
            .FromMaybe(false))
     return;
   m_console.Reset(isolate, console);
   m_console.SetWeak();
 }
 
 InspectedContext::~InspectedContext() {
   if (!m_console.IsEmpty()) {
     v8::HandleScope scope(isolate());
     V8Console::clearInspectedContextIfNeeded(context(),
                                              m_console.Get(isolate()));
   }
 }
 
+// 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());
+}
+
 v8::Local<v8::Context> InspectedContext::context() const {
   return m_context.Get(isolate());
 }
 
 v8::Isolate* InspectedContext::isolate() const {
   return m_inspector->isolate();
 }
 
 bool InspectedContext::createInjectedScript() {
   DCHECK(!m_injectedScript);
   std::unique_ptr<InjectedScript> injectedScript = InjectedScript::create(this);
   // InjectedScript::create can destroy |this|.
   if (!injectedScript) return false;
   m_injectedScript = std::move(injectedScript);
   return true;
 }
 
 void InspectedContext::discardInjectedScript() { m_injectedScript.reset(); }
 
 }  // namespace v8_inspector