Revert of [debugger api] remove legacy JSON debug protocol.

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 8878 matching lines @@
   internal_isolate->stack_guard()->ClearDebugBreak();
 }
 
 
 bool Debug::CheckDebugBreak(Isolate* isolate) {
   i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
   return internal_isolate->stack_guard()->CheckDebugBreak();
 }
 
 
+void Debug::SetMessageHandler(Isolate* isolate,
+                              v8::Debug::MessageHandler handler) {
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  ENTER_V8(i_isolate);
+  i_isolate->debug()->SetMessageHandler(handler);
+}
+
+
+void Debug::SendCommand(Isolate* isolate,
+                        const uint16_t* command,
+                        int length,
+                        ClientData* client_data) {
+  i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  internal_isolate->debug()->EnqueueCommandMessage(
+      i::Vector<const uint16_t>(command, length), client_data);
+}
+
+
 MaybeLocal<Value> Debug::Call(Local<Context> context,
                               v8::Local<v8::Function> fun,
                               v8::Local<v8::Value> data) {
   PREPARE_FOR_EXECUTION(context, Debug, Call, Value);
   i::Handle<i::Object> data_obj;
   if (data.IsEmpty()) {
     data_obj = isolate->factory()->undefined_value();
   } else {
     data_obj = Utils::OpenHandle(*data);
   }
@@ skipping 19 matching lines @@
   const int kArgc = 1;
   v8::Local<v8::Value> argv[kArgc] = {obj};
   Local<Value> result;
   has_pending_exception =
       !v8_fun->Call(context, Utils::ToLocal(debug), kArgc, argv)
            .ToLocal(&result);
   RETURN_ON_FAILED_EXECUTION(Value);
   RETURN_ESCAPED(result);
 }
 
+void Debug::ProcessDebugMessages(Isolate* isolate) {
+  reinterpret_cast<i::Isolate*>(isolate)->debug()->ProcessDebugMessages(true);
+}
 
+
 Local<Context> Debug::GetDebugContext(Isolate* isolate) {
   return debug::GetDebugContext(isolate);
 }
 
 
 MaybeLocal<Context> Debug::GetDebuggedContext(Isolate* isolate) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   ENTER_V8(i_isolate);
   if (!i_isolate->debug()->in_debug_scope()) return MaybeLocal<Context>();
   i::Handle<i::Object> calling = i_isolate->GetCallingNativeContext();
@@ skipping 1050 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