[inspector] Refactor inspector test

test/inspector/inspector-test.cc

Index: test/inspector/inspector-test.cc
diff --git a/test/inspector/inspector-test.cc b/test/inspector/inspector-test.cc
index f8e96ed90b2dbdf838e19490a68c66b244e64c70..2e105c54d90121aa1309ab3d9450f2397a647844 100644
--- a/test/inspector/inspector-test.cc
+++ b/test/inspector/inspector-test.cc
@@ -51,6 +51,196 @@ v8::Local<v8::String> ToV8String(v8::Isolate* isolate, const char* str) {
       .ToLocalChecked();
 }
 
+v8::internal::Vector<uint16_t> ToVector(
+    const v8_inspector::StringView& string) {
+  v8::internal::Vector<uint16_t> buffer =
+      v8::internal::Vector<uint16_t>::New(static_cast<int>(string.length()));
+  for (size_t i = 0; i < string.length(); i++) {
+    if (string.is8Bit())
+      buffer[i] = string.characters8()[i];
+    else
+      buffer[i] = string.characters16()[i];
+  }
+  return buffer;
+}
+
+class CreateContextGroupTask : public TaskRunner::Task {
+ public:
+  CreateContextGroupTask(v8::base::Semaphore* ready_semaphore,
+                         int* context_group_id)
+      : ready_semaphore_(ready_semaphore),
+        context_group_id_(context_group_id) {}
+  virtual ~CreateContextGroupTask() = default;
+  bool is_inspector_task() final { return true; }
+
+ private:
+  void Run() override {
+    *context_group_id_ = data()->CreateContextGroup();
+    if (ready_semaphore_) ready_semaphore_->Signal();
+  }
+
+  v8::base::Semaphore* ready_semaphore_;
+  int* context_group_id_;
+};
+
+class ConnectSessionTask : public TaskRunner::Task {
+ public:
+  ConnectSessionTask(v8::base::Semaphore* ready_semaphore, int context_group_id,
+                     const v8::internal::Vector<uint16_t>& state,
+                     int* session_id)
+      : ready_semaphore_(ready_semaphore),
+        context_group_id_(context_group_id),
+        state_(state),
+        session_id_(session_id) {}
+  virtual ~ConnectSessionTask() = default;
+  bool is_inspector_task() final { return true; }
+
+ private:
+  void Run() override {
+    v8_inspector::StringView state(state_.start(), state_.length());
+    *session_id_ =
+        data()->inspector()->ConnectSession(context_group_id_, state);
+    if (ready_semaphore_) ready_semaphore_->Signal();
+  }
+
+  v8::base::Semaphore* ready_semaphore_;
+  int context_group_id_;
+  const v8::internal::Vector<uint16_t>& state_;
+  int* session_id_;
+};
+
+class DisconnectSessionTask : public TaskRunner::Task {
+ public:
+  DisconnectSessionTask(v8::base::Semaphore* ready_semaphore, int session_id,
+                        v8::internal::Vector<uint16_t>* state)
+      : ready_semaphore_(ready_semaphore),
+        session_id_(session_id),
+        state_(state) {}
+  virtual ~DisconnectSessionTask() = default;
+  bool is_inspector_task() final { return true; }
+
+ private:
+  void Run() override {
+    std::unique_ptr<v8_inspector::StringBuffer> state =
+        data()->inspector()->DisconnectSession(session_id_);
+    *state_ = ToVector(state->string());
+    if (ready_semaphore_) ready_semaphore_->Signal();
+  }
+
+  v8::base::Semaphore* ready_semaphore_;
+  int session_id_;
+  v8::internal::Vector<uint16_t>* state_;
+};
+
+class SendMessageToBackendTask : public TaskRunner::Task {
+ public:
+  explicit SendMessageToBackendTask(
+      int session_id, const v8::internal::Vector<uint16_t>& message)
+      : session_id_(session_id), message_(message) {}
+  bool is_inspector_task() final { return true; }
+
+ private:
+  void Run() override {
+    v8_inspector::StringView message_view(message_.start(), message_.length());
+    data()->inspector()->SendMessage(session_id_, message_view);
+  }
+
+  int session_id_;
+  v8::internal::Vector<uint16_t> message_;
+};
+
+class SchedulePauseOnNextStatementTask : public TaskRunner::Task {
+ public:
+  SchedulePauseOnNextStatementTask(
+      v8::base::Semaphore* ready_semaphore, int context_group_id,
+      const v8::internal::Vector<uint16_t>& reason,
+      const v8::internal::Vector<uint16_t>& details)
+      : ready_semaphore_(ready_semaphore),
+        context_group_id_(context_group_id),
+        reason_(reason),
+        details_(details) {}
+  virtual ~SchedulePauseOnNextStatementTask() = default;
+  bool is_inspector_task() final { return true; }
+
+ private:
+  void Run() override {
+    v8_inspector::StringView reason(reason_.start(), reason_.length());
+    v8_inspector::StringView details(details_.start(), details_.length());
+    data()->inspector()->SchedulePauseOnNextStatement(context_group_id_, reason,
+                                                      details);
+    if (ready_semaphore_) ready_semaphore_->Signal();
+  }
+
+  v8::base::Semaphore* ready_semaphore_;
+  int context_group_id_;
+  const v8::internal::Vector<uint16_t>& reason_;
+  const v8::internal::Vector<uint16_t>& details_;
+};
+
+class CancelPauseOnNextStatementTask : public TaskRunner::Task {
+ public:
+  CancelPauseOnNextStatementTask(v8::base::Semaphore* ready_semaphore,
+                                 int context_group_id)
+      : ready_semaphore_(ready_semaphore),
+        context_group_id_(context_group_id) {}
+  virtual ~CancelPauseOnNextStatementTask() = default;
+  bool is_inspector_task() final { return true; }
+
+ private:
+  void Run() override {
+    data()->inspector()->CancelPauseOnNextStatement(context_group_id_);
+    if (ready_semaphore_) ready_semaphore_->Signal();
+  }
+
+  v8::base::Semaphore* ready_semaphore_;
+  int context_group_id_;
+};
+
+class SendMessageToFrontendTask : public TaskRunner::Task {
+ public:
+  SendMessageToFrontendTask(int context_group_id, int session_id,
+                            const v8::internal::Vector<uint16_t>& message)
+      : context_group_id_(context_group_id),
+        session_id_(session_id),
+        message_(message) {}
+  virtual ~SendMessageToFrontendTask() {}
+
+  bool is_inspector_task() final { return false; }
+
+  static void Register(int session_id, v8::Isolate* isolate,
+                       v8::Local<v8::Function> dispatcher) {
+    dispatchers_[session_id].Reset(isolate, dispatcher);
+  }
+
+  static void Unregister(int session_id) { dispatchers_.erase(session_id); }
+
+ private:
+  void Run() override {
+    v8::MicrotasksScope microtasks_scope(isolate(),
+                                         v8::MicrotasksScope::kRunMicrotasks);
+    v8::HandleScope handle_scope(isolate());
+    v8::Local<v8::Context> context = data()->GetContext(context_group_id_);
+    v8::Context::Scope context_scope(context);
+
+    if (dispatchers_.find(session_id_) == dispatchers_.end()) return;
+    v8::Local<v8::Function> function = dispatchers_[session_id_].Get(isolate());
+    v8::Local<v8::Value> message =
+        v8::String::NewFromTwoByte(isolate(), message_.start(),
+                                   v8::NewStringType::kNormal,
+                                   static_cast<int>(message_.size()))
+            .ToLocalChecked();
+    v8::MaybeLocal<v8::Value> result;
+    result = function->Call(context, context->Global(), 1, &message);
+  }
+
+  static std::map<int, v8::Global<v8::Function>> dispatchers_;
+  int context_group_id_;
+  int session_id_;
+  v8::internal::Vector<uint16_t> message_;
+};
+
+std::map<int, v8::Global<v8::Function>> SendMessageToFrontendTask::dispatchers_;
+
 class UtilsExtension : public IsolateData::SetupGlobalTask {
  public:
   ~UtilsExtension() override = default;
@@ -82,16 +272,21 @@ class UtilsExtension : public IsolateData::SetupGlobalTask {
     utils->Set(ToV8String(isolate, "cancelPauseOnNextStatement"),
                v8::FunctionTemplate::New(
                    isolate, &UtilsExtension::CancelPauseOnNextStatement));
-    utils->Set(ToV8String(isolate, "reconnect"),
-               v8::FunctionTemplate::New(isolate, &UtilsExtension::Reconnect));
-    utils->Set(ToV8String(isolate, "disconnect"),
-               v8::FunctionTemplate::New(isolate, &UtilsExtension::Disconnect));
     utils->Set(ToV8String(isolate, "setLogConsoleApiMessageCalls"),
                v8::FunctionTemplate::New(
                    isolate, &UtilsExtension::SetLogConsoleApiMessageCalls));
     utils->Set(ToV8String(isolate, "createContextGroup"),
                v8::FunctionTemplate::New(isolate,
                                          &UtilsExtension::CreateContextGroup));
+    utils->Set(
+        ToV8String(isolate, "connectSession"),
+        v8::FunctionTemplate::New(isolate, &UtilsExtension::ConnectSession));
+    utils->Set(
+        ToV8String(isolate, "disconnectSession"),
+        v8::FunctionTemplate::New(isolate, &UtilsExtension::DisconnectSession));
+    utils->Set(ToV8String(isolate, "sendMessageToBackend"),
+               v8::FunctionTemplate::New(
+                   isolate, &UtilsExtension::SendMessageToBackend));
     global->Set(ToV8String(isolate, "utils"), utils);
   }
 
@@ -99,13 +294,8 @@ class UtilsExtension : public IsolateData::SetupGlobalTask {
     backend_runner_ = runner;
   }
 
-  static void set_inspector_client(InspectorClientImpl* client) {
-    inspector_client_ = client;
-  }
-
  private:
   static TaskRunner* backend_runner_;
-  static InspectorClientImpl* inspector_client_;
 
   static void Print(const v8::FunctionCallbackInfo<v8::Value>& args) {
     for (int i = 0; i < args.Length(); i++) {
@@ -189,27 +379,31 @@ class UtilsExtension : public IsolateData::SetupGlobalTask {
     }
     v8::internal::Vector<const char> chars;
     v8::Isolate* isolate = args.GetIsolate();
+    v8::Local<v8::Context> context = isolate->GetCurrentContext();
+    IsolateData* data = IsolateData::FromContext(context);
+    int context_group_id = data->GetContextGroupId(context);
     if (ReadFile(isolate, args[0], &chars)) {
-      ExecuteStringTask(chars).RunOnTaskRunner(
-          IsolateData::FromContext(isolate->GetCurrentContext())
-              ->task_runner());
+      ExecuteStringTask(chars, context_group_id).RunOnIsolate(data);
     }
   }
 
   static void CompileAndRunWithOrigin(
       const v8::FunctionCallbackInfo<v8::Value>& args) {
-    if (args.Length() != 5 || !args[0]->IsString() || !args[1]->IsString() ||
-        !args[2]->IsInt32() || !args[3]->IsInt32() || !args[4]->IsBoolean()) {
+    if (args.Length() != 6 || !args[0]->IsInt32() || !args[1]->IsString() ||
+        !args[2]->IsString() || !args[3]->IsInt32() || !args[4]->IsInt32() ||
+        !args[5]->IsBoolean()) {
       fprintf(stderr,
-              "Internal error: compileAndRunWithOrigin(source, name, line, "
+              "Internal error: compileAndRunWithOrigin(context_group_id, "
+              "source, name, line, "
               "column, is_module).");
       Exit();
     }
 
     backend_runner_->Append(new ExecuteStringTask(
-        ToVector(args[0].As<v8::String>()), args[1].As<v8::String>(),
-        args[2].As<v8::Int32>(), args[3].As<v8::Int32>(),
-        args[4].As<v8::Boolean>(), nullptr, nullptr));
+        nullptr, args[0].As<v8::Int32>()->Value(), nullptr,
+        ToVector(args[1].As<v8::String>()), args[2].As<v8::String>(),
+        args[3].As<v8::Int32>(), args[4].As<v8::Int32>(),
+        args[5].As<v8::Boolean>()));
   }
 
   static void SetCurrentTimeMSForTest(
@@ -218,7 +412,7 @@ class UtilsExtension : public IsolateData::SetupGlobalTask {
       fprintf(stderr, "Internal error: setCurrentTimeMSForTest(time).");
       Exit();
     }
-    inspector_client_->setCurrentTimeMSForTest(
+    backend_runner_->data()->inspector()->SetCurrentTimeMSForTest(
         args[0].As<v8::Number>()->Value());
   }
 
@@ -228,76 +422,125 @@ class UtilsExtension : public IsolateData::SetupGlobalTask {
       fprintf(stderr, "Internal error: setMemoryInfoForTest(value).");
       Exit();
     }
-    inspector_client_->setMemoryInfoForTest(args[0]);
+    backend_runner_->data()->inspector()->SetMemoryInfoForTest(args[0]);
   }
 
   static void SchedulePauseOnNextStatement(
       const v8::FunctionCallbackInfo<v8::Value>& args) {
-    if (args.Length() != 2 || !args[0]->IsString() || !args[1]->IsString()) {
-      fprintf(
-          stderr,
-          "Internal error: schedulePauseOnNextStatement('reason', 'details').");
+    if (args.Length() != 3 || !args[0]->IsInt32() || !args[1]->IsString() ||
+        !args[2]->IsString()) {
+      fprintf(stderr,
+              "Internal error: schedulePauseOnNextStatement(context_group_id, "
+              "'reason', 'details').");
       Exit();
     }
-    v8::internal::Vector<uint16_t> reason = ToVector(args[0].As<v8::String>());
-    v8_inspector::StringView reason_view(reason.start(), reason.length());
-    v8::internal::Vector<uint16_t> details = ToVector(args[1].As<v8::String>());
-    v8_inspector::StringView details_view(details.start(), details.length());
-    inspector_client_->session()->schedulePauseOnNextStatement(reason_view,
-                                                               details_view);
+    v8::internal::Vector<uint16_t> reason = ToVector(args[1].As<v8::String>());
+    v8::internal::Vector<uint16_t> details = ToVector(args[2].As<v8::String>());
+    v8::base::Semaphore ready_semaphore(0);
+    backend_runner_->Append(new SchedulePauseOnNextStatementTask(
+        &ready_semaphore, args[0].As<v8::Int32>()->Value(), reason, details));
+    ready_semaphore.Wait();
   }
 
   static void CancelPauseOnNextStatement(
       const v8::FunctionCallbackInfo<v8::Value>& args) {
-    if (args.Length() != 0) {
-      fprintf(stderr, "Internal error: cancelPauseOnNextStatement().");
+    if (args.Length() != 1 || !args[0]->IsInt32()) {
+      fprintf(stderr,
+              "Internal error: cancelPauseOnNextStatement(context_group_id).");
       Exit();
     }
-    inspector_client_->session()->cancelPauseOnNextStatement();
+    v8::base::Semaphore ready_semaphore(0);
+    backend_runner_->Append(new CancelPauseOnNextStatementTask(
+        &ready_semaphore, args[0].As<v8::Int32>()->Value()));
+    ready_semaphore.Wait();
   }
 
-  static void Reconnect(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  static void SetLogConsoleApiMessageCalls(
+      const v8::FunctionCallbackInfo<v8::Value>& args) {
+    if (args.Length() != 1 || !args[0]->IsBoolean()) {
+      fprintf(stderr, "Internal error: setLogConsoleApiMessageCalls(bool).");
+      Exit();
+    }
+    backend_runner_->data()->inspector()->SetLogConsoleApiMessageCalls(
+        args[0].As<v8::Boolean>()->Value());
+  }
+
+  static void CreateContextGroup(
+      const v8::FunctionCallbackInfo<v8::Value>& args) {
     if (args.Length() != 0) {
-      fprintf(stderr, "Internal error: reconnect().");
+      fprintf(stderr, "Internal error: createContextGroup().");
       Exit();
     }
     v8::base::Semaphore ready_semaphore(0);
-    inspector_client_->scheduleReconnect(&ready_semaphore);
+    int context_group_id = 0;
+    backend_runner_->Append(
+        new CreateContextGroupTask(&ready_semaphore, &context_group_id));
     ready_semaphore.Wait();
+    args.GetReturnValue().Set(
+        v8::Int32::New(args.GetIsolate(), context_group_id));
   }
 
-  static void Disconnect(const v8::FunctionCallbackInfo<v8::Value>& args) {
-    if (args.Length() != 0) {
-      fprintf(stderr, "Internal error: disconnect().");
+  static void ConnectSession(const v8::FunctionCallbackInfo<v8::Value>& args) {
+    if (args.Length() != 3 || !args[0]->IsInt32() || !args[1]->IsString() ||
+        !args[2]->IsFunction()) {
+      fprintf(stderr,
+              "Internal error: connectionSession(context_group_id, state, "
+              "dispatch).");
       Exit();
     }
+    v8::internal::Vector<uint16_t> state = ToVector(args[1].As<v8::String>());
     v8::base::Semaphore ready_semaphore(0);
-    inspector_client_->scheduleDisconnect(&ready_semaphore);
+    int session_id = 0;
+    backend_runner_->Append(new ConnectSessionTask(
+        &ready_semaphore, args[0].As<v8::Int32>()->Value(), state,
+        &session_id));
     ready_semaphore.Wait();
+    SendMessageToFrontendTask::Register(session_id, args.GetIsolate(),
+                                        args[2].As<v8::Function>());
+    args.GetReturnValue().Set(v8::Int32::New(args.GetIsolate(), session_id));
   }
 
-  static void SetLogConsoleApiMessageCalls(
+  static void DisconnectSession(
       const v8::FunctionCallbackInfo<v8::Value>& args) {
-    if (args.Length() != 1 || !args[0]->IsBoolean()) {
-      fprintf(stderr, "Internal error: setLogConsoleApiMessageCalls(bool).");
+    if (args.Length() != 1 || !args[0]->IsInt32()) {
+      fprintf(stderr, "Internal error: disconnectionSession(session_id).");
       Exit();
     }
-    inspector_client_->setLogConsoleApiMessageCalls(
-        args[0].As<v8::Boolean>()->Value());
+    int session_id = args[0].As<v8::Int32>()->Value();
+    SendMessageToFrontendTask::Unregister(session_id);
+    v8::base::Semaphore ready_semaphore(0);
+    v8::internal::Vector<uint16_t> state;
+    backend_runner_->Append(
+        new DisconnectSessionTask(&ready_semaphore, session_id, &state));
+    ready_semaphore.Wait();
+    args.GetReturnValue().Set(
+        v8::String::NewFromTwoByte(args.GetIsolate(), state.start(),
+                                   v8::NewStringType::kNormal,
+                                   static_cast<int>(state.size()))
+            .ToLocalChecked());
   }
 
-  static void CreateContextGroup(
-      const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void SendMessageToBackend(
+      const v8::FunctionCallbackInfo<v8::Value>& args) {
+    if (args.Length() != 2 || !args[0]->IsInt32() || !args[1]->IsString()) {
+      fprintf(stderr,
+              "Internal error: sendMessageToBackend(session_id, message).");
+      Exit();
+    }
+    backend_runner_->Append(new SendMessageToBackendTask(
+        args[0].As<v8::Int32>()->Value(), ToVector(args[1].As<v8::String>())));
+  }
 };
 
 TaskRunner* UtilsExtension::backend_runner_ = nullptr;
-InspectorClientImpl* UtilsExtension::inspector_client_ = nullptr;
 
 class SetTimeoutTask : public AsyncTask {
  public:
-  SetTimeoutTask(v8::Isolate* isolate, v8::Local<v8::Function> function,
-                 const char* task_name, v8_inspector::V8Inspector* inspector)
-      : AsyncTask(task_name, inspector), function_(isolate, function) {}
+  SetTimeoutTask(IsolateData* data, int context_group_id, const char* task_name,
+                 v8::Local<v8::Function> function)
+      : AsyncTask(data, task_name),
+        function_(data->isolate(), function),
+        context_group_id_(context_group_id) {}
   virtual ~SetTimeoutTask() {}
 
   bool is_inspector_task() final { return false; }
@@ -307,7 +550,7 @@ class SetTimeoutTask : public AsyncTask {
     v8::MicrotasksScope microtasks_scope(isolate(),
                                          v8::MicrotasksScope::kRunMicrotasks);
     v8::HandleScope handle_scope(isolate());
-    v8::Local<v8::Context> context = default_context();
+    v8::Local<v8::Context> context = data()->GetContext(context_group_id_);
     v8::Context::Scope context_scope(context);
 
     v8::Local<v8::Function> function = function_.Get(isolate());
@@ -316,6 +559,7 @@ class SetTimeoutTask : public AsyncTask {
   }
 
   v8::Global<v8::Function> function_;
+  int context_group_id_;
 };
 
 class SetTimeoutExtension : public IsolateData::SetupGlobalTask {
@@ -332,26 +576,27 @@ class SetTimeoutExtension : public IsolateData::SetupGlobalTask {
     if (args.Length() != 2 || !args[1]->IsNumber() ||
         (!args[0]->IsFunction() && !args[0]->IsString()) ||
         args[1].As<v8::Number>()->Value() != 0.0) {
-      fprintf(stderr,
-              "Internal error: only setTimeout(function, 0) is supported.");
+      fprintf(
+          stderr,
+          "Internal error: only setTimeout(function|code, 0) is supported.");
       Exit();
     }
     v8::Isolate* isolate = args.GetIsolate();
     v8::Local<v8::Context> context = isolate->GetCurrentContext();
+    IsolateData* data = IsolateData::FromContext(context);
+    int context_group_id = data->GetContextGroupId(context);
     std::unique_ptr<TaskRunner::Task> task;
-    v8_inspector::V8Inspector* inspector =
-        InspectorClientImpl::InspectorFromContext(context);
     if (args[0]->IsFunction()) {
-      task.reset(new SetTimeoutTask(isolate,
-                                    v8::Local<v8::Function>::Cast(args[0]),
-                                    "setTimeout", inspector));
+      task.reset(new SetTimeoutTask(data, context_group_id, "setTimeout",
+                                    v8::Local<v8::Function>::Cast(args[0])));
     } else {
       task.reset(new ExecuteStringTask(
+          data, context_group_id, "setTimeout",
           ToVector(args[0].As<v8::String>()), v8::String::Empty(isolate),
           v8::Integer::New(isolate, 0), v8::Integer::New(isolate, 0),
-          v8::Boolean::New(isolate, false), "setTimeout", inspector));
+          v8::Boolean::New(isolate, false)));
     }
-    IsolateData::FromContext(context)->task_runner()->Append(task.release());
+    data->task_runner()->Append(task.release());
   }
 };
 
@@ -368,12 +613,12 @@ class InspectorExtension : public IsolateData::SetupGlobalTask {
   void Run(v8::Isolate* isolate,
            v8::Local<v8::ObjectTemplate> global) override {
     v8::Local<v8::ObjectTemplate> inspector = v8::ObjectTemplate::New(isolate);
-    inspector->Set(
-        ToV8String(isolate, "attachInspector"),
-        v8::FunctionTemplate::New(isolate, &InspectorExtension::Attach));
-    inspector->Set(
-        ToV8String(isolate, "detachInspector"),
-        v8::FunctionTemplate::New(isolate, &InspectorExtension::Detach));
+    inspector->Set(ToV8String(isolate, "fireContextCreated"),
+                   v8::FunctionTemplate::New(
+                       isolate, &InspectorExtension::FireContextCreated));
+    inspector->Set(ToV8String(isolate, "fireContextDestroyed"),
+                   v8::FunctionTemplate::New(
+                       isolate, &InspectorExtension::FireContextDestroyed));
     inspector->Set(ToV8String(isolate, "setMaxAsyncTaskStacks"),
                    v8::FunctionTemplate::New(
                        isolate, &InspectorExtension::SetMaxAsyncTaskStacks));
@@ -398,29 +643,19 @@ class InspectorExtension : public IsolateData::SetupGlobalTask {
   }
 
  private:
-  static void Attach(const v8::FunctionCallbackInfo<v8::Value>& args) {
-    v8::Isolate* isolate = args.GetIsolate();
-    v8::Local<v8::Context> context = isolate->GetCurrentContext();
-    v8_inspector::V8Inspector* inspector =
-        InspectorClientImpl::InspectorFromContext(context);
-    if (!inspector) {
-      fprintf(stderr, "Inspector client not found - cannot attach!");
-      Exit();
-    }
-    inspector->contextCreated(
-        v8_inspector::V8ContextInfo(context, 1, v8_inspector::StringView()));
+  static void FireContextCreated(
+      const v8::FunctionCallbackInfo<v8::Value>& args) {
+    v8::Local<v8::Context> context = args.GetIsolate()->GetCurrentContext();
+    IsolateData* data = IsolateData::FromContext(context);
+    data->inspector()->ContextCreated(context,
+                                      data->GetContextGroupId(context));
   }
 
-  static void Detach(const v8::FunctionCallbackInfo<v8::Value>& args) {
-    v8::Isolate* isolate = args.GetIsolate();
-    v8::Local<v8::Context> context = isolate->GetCurrentContext();
-    v8_inspector::V8Inspector* inspector =
-        InspectorClientImpl::InspectorFromContext(context);
-    if (!inspector) {
-      fprintf(stderr, "Inspector client not found - cannot detach!");
-      Exit();
-    }
-    inspector->contextDestroyed(context);
+  static void FireContextDestroyed(
+      const v8::FunctionCallbackInfo<v8::Value>& args) {
+    v8::Local<v8::Context> context = args.GetIsolate()->GetCurrentContext();
+    IsolateData* data = IsolateData::FromContext(context);
+    data->inspector()->ContextDestroyed(context);
   }
 
   static void SetMaxAsyncTaskStacks(
@@ -429,12 +664,11 @@ class InspectorExtension : public IsolateData::SetupGlobalTask {
       fprintf(stderr, "Internal error: setMaxAsyncTaskStacks(max).");
       Exit();
     }
-    v8_inspector::V8Inspector* inspector =
-        InspectorClientImpl::InspectorFromContext(
-            args.GetIsolate()->GetCurrentContext());
-    CHECK(inspector);
     v8_inspector::SetMaxAsyncTaskStacksForTest(
-        inspector, args[0].As<v8::Int32>()->Value());
+        IsolateData::FromContext(args.GetIsolate()->GetCurrentContext())
+            ->inspector()
+            ->inspector(),
+        args[0].As<v8::Int32>()->Value());
   }
 
   static void DumpAsyncTaskStacksStateForTest(
@@ -443,11 +677,10 @@ class InspectorExtension : public IsolateData::SetupGlobalTask {
       fprintf(stderr, "Internal error: dumpAsyncTaskStacksStateForTest().");
       Exit();
     }
-    v8_inspector::V8Inspector* inspector =
-        InspectorClientImpl::InspectorFromContext(
-            args.GetIsolate()->GetCurrentContext());
-    CHECK(inspector);
-    v8_inspector::DumpAsyncTaskStacksStateForTest(inspector);
+    v8_inspector::DumpAsyncTaskStacksStateForTest(
+        IsolateData::FromContext(args.GetIsolate()->GetCurrentContext())
+            ->inspector()
+            ->inspector());
   }
 
   static void BreakProgram(const v8::FunctionCallbackInfo<v8::Value>& args) {
@@ -455,16 +688,14 @@ class InspectorExtension : public IsolateData::SetupGlobalTask {
       fprintf(stderr, "Internal error: breakProgram('reason', 'details').");
       Exit();
     }
-    v8_inspector::V8InspectorSession* session =
-        InspectorClientImpl::SessionFromContext(
-            args.GetIsolate()->GetCurrentContext());
-    CHECK(session);
-
+    v8::Local<v8::Context> context = args.GetIsolate()->GetCurrentContext();
+    IsolateData* data = IsolateData::FromContext(context);
     v8::internal::Vector<uint16_t> reason = ToVector(args[0].As<v8::String>());
     v8_inspector::StringView reason_view(reason.start(), reason.length());
     v8::internal::Vector<uint16_t> details = ToVector(args[1].As<v8::String>());
     v8_inspector::StringView details_view(details.start(), details.length());
-    session->breakProgram(reason_view, details_view);
+    data->inspector()->BreakProgram(data->GetContextGroupId(context),
+                                    reason_view, details_view);
   }
 
   static void CreateObjectWithStrictCheck(
@@ -485,24 +716,23 @@ class InspectorExtension : public IsolateData::SetupGlobalTask {
       const v8::FunctionCallbackInfo<v8::Value>& args) {
     if (args.Length() != 3 || !args[0]->IsFunction() || !args[1]->IsString() ||
         !args[2]->IsString()) {
-      fprintf(stderr, "Internal error: breakProgram('reason', 'details').");
+      fprintf(stderr,
+              "Internal error: callWithScheduledBreak('reason', 'details').");
       Exit();
     }
-    v8_inspector::V8InspectorSession* session =
-        InspectorClientImpl::SessionFromContext(
-            args.GetIsolate()->GetCurrentContext());
-    CHECK(session);
-
     v8::internal::Vector<uint16_t> reason = ToVector(args[1].As<v8::String>());
     v8_inspector::StringView reason_view(reason.start(), reason.length());
     v8::internal::Vector<uint16_t> details = ToVector(args[2].As<v8::String>());
     v8_inspector::StringView details_view(details.start(), details.length());
-    session->schedulePauseOnNextStatement(reason_view, details_view);
     v8::Local<v8::Context> context = args.GetIsolate()->GetCurrentContext();
+    IsolateData* data = IsolateData::FromContext(context);
+    int context_group_id = data->GetContextGroupId(context);
+    data->inspector()->SchedulePauseOnNextStatement(context_group_id,
+                                                    reason_view, details_view);
     v8::MaybeLocal<v8::Value> result;
     result = args[0].As<v8::Function>()->Call(context, context->Global(), 0,
                                               nullptr);
-    session->cancelPauseOnNextStatement();
+    data->inspector()->CancelPauseOnNextStatement(context_group_id);
   }
 
   static void AllowAccessorFormatting(
@@ -524,68 +754,22 @@ class InspectorExtension : public IsolateData::SetupGlobalTask {
   }
 };
 
-void UtilsExtension::CreateContextGroup(
-    const v8::FunctionCallbackInfo<v8::Value>& args) {
-  if (args.Length() != 0) {
-    fprintf(stderr, "Internal error: createContextGroup().");
-    Exit();
-  }
-  v8::base::Semaphore ready_semaphore(0);
-  int context_group_id = 0;
-  IsolateData::SetupGlobalTasks setup_global;
-  setup_global.emplace_back(new SetTimeoutExtension());
-  setup_global.emplace_back(new InspectorExtension());
-  inspector_client_->scheduleCreateContextGroup(
-      std::move(setup_global), &ready_semaphore, &context_group_id);
-  ready_semaphore.Wait();
-  args.GetReturnValue().Set(
-      v8::Int32::New(args.GetIsolate(), context_group_id));
-}
-
-v8::Local<v8::String> ToString(v8::Isolate* isolate,
-                               const v8_inspector::StringView& string) {
-  if (string.is8Bit())
-    return v8::String::NewFromOneByte(isolate, string.characters8(),
-                                      v8::NewStringType::kNormal,
-                                      static_cast<int>(string.length()))
-        .ToLocalChecked();
-  else
-    return v8::String::NewFromTwoByte(isolate, string.characters16(),
-                                      v8::NewStringType::kNormal,
-                                      static_cast<int>(string.length()))
-        .ToLocalChecked();
-}
-
 class FrontendChannelImpl : public InspectorClientImpl::FrontendChannel {
  public:
-  explicit FrontendChannelImpl(TaskRunner* frontend_task_runner)
-      : frontend_task_runner_(frontend_task_runner) {}
+  FrontendChannelImpl(TaskRunner* frontend_task_runner, int context_group_id)
+      : frontend_task_runner_(frontend_task_runner),
+        context_group_id_(context_group_id) {}
   virtual ~FrontendChannelImpl() {}
 
-  void SendMessageToFrontend(const v8_inspector::StringView& message) final {
-    v8::Isolate* isolate = v8::Isolate::GetCurrent();
-    v8::HandleScope scope(v8::Isolate::GetCurrent());
-
-    v8::Local<v8::String> prefix =
-        v8::String::NewFromUtf8(isolate, "InspectorTest._dispatchMessage(",
-                                v8::NewStringType::kInternalized)
-            .ToLocalChecked();
-    v8::Local<v8::String> message_string = ToString(isolate, message);
-    v8::Local<v8::String> suffix =
-        v8::String::NewFromUtf8(isolate, ")", v8::NewStringType::kInternalized)
-            .ToLocalChecked();
-
-    v8::Local<v8::String> result = v8::String::Concat(prefix, message_string);
-    result = v8::String::Concat(result, suffix);
-
-    frontend_task_runner_->Append(new ExecuteStringTask(
-        ToVector(result), v8::String::Empty(isolate),
-        v8::Integer::New(isolate, 0), v8::Integer::New(isolate, 0),
-        v8::Boolean::New(isolate, false), nullptr, nullptr));
+  void SendMessageToFrontend(int session_id,
+                             const v8_inspector::StringView& message) final {
+    frontend_task_runner_->Append(new SendMessageToFrontendTask(
+        context_group_id_, session_id, ToVector(message)));
   }
 
  private:
   TaskRunner* frontend_task_runner_;
+  int context_group_id_;
 };
 
 }  //  namespace
@@ -610,28 +794,27 @@ int main(int argc, char* argv[]) {
     }
   }
 
-  IsolateData::SetupGlobalTasks backend_extensions;
-  backend_extensions.emplace_back(new SetTimeoutExtension());
-  backend_extensions.emplace_back(new InspectorExtension());
-  TaskRunner backend_runner(std::move(backend_extensions), false,
-                            &ready_semaphore,
-                            startup_data.data ? &startup_data : nullptr);
-  ready_semaphore.Wait();
-  SendMessageToBackendExtension::set_backend_task_runner(&backend_runner);
-  UtilsExtension::set_backend_task_runner(&backend_runner);
-
   IsolateData::SetupGlobalTasks frontend_extensions;
   frontend_extensions.emplace_back(new UtilsExtension());
-  frontend_extensions.emplace_back(new SendMessageToBackendExtension());
   TaskRunner frontend_runner(std::move(frontend_extensions), true,
-                             &ready_semaphore, nullptr);
+                             &ready_semaphore, nullptr, nullptr);
+  ready_semaphore.Wait();
+
+  int frontend_context_group_id = 0;
+  frontend_runner.Append(
+      new CreateContextGroupTask(&ready_semaphore, &frontend_context_group_id));
   ready_semaphore.Wait();
 
-  FrontendChannelImpl frontend_channel(&frontend_runner);
-  InspectorClientImpl inspector_client(&backend_runner, &frontend_channel,
-                                       &ready_semaphore);
+  IsolateData::SetupGlobalTasks backend_extensions;
+  backend_extensions.emplace_back(new SetTimeoutExtension());
+  backend_extensions.emplace_back(new InspectorExtension());
+  FrontendChannelImpl frontend_channel(&frontend_runner,
+                                       frontend_context_group_id);
+  TaskRunner backend_runner(
+      std::move(backend_extensions), false, &ready_semaphore,
+      startup_data.data ? &startup_data : nullptr, &frontend_channel);
   ready_semaphore.Wait();
-  UtilsExtension::set_inspector_client(&inspector_client);
+  UtilsExtension::set_backend_task_runner(&backend_runner);
 
   task_runners.push_back(&frontend_runner);
   task_runners.push_back(&backend_runner);
@@ -648,7 +831,8 @@ int main(int argc, char* argv[]) {
               argv[i]);
       Exit();
     }
-    frontend_runner.Append(new ExecuteStringTask(chars));
+    frontend_runner.Append(
+        new ExecuteStringTask(chars, frontend_context_group_id));
   }
 
   frontend_runner.Join();