[debugger api] remove legacy JSON debug protocol.

include/v8-debug.h

Index: include/v8-debug.h
diff --git a/include/v8-debug.h b/include/v8-debug.h
index 777b8aaa3e645a1c6024d46ebab5bbc70754cd1b..bd8568072ef99ff991ac2a0af2a74bfdf7673b7f 100644
--- a/include/v8-debug.h
+++ b/include/v8-debug.h
@@ -116,9 +116,7 @@ class V8_EXPORT Debug {
     virtual Local<Value> GetCallbackData() const = 0;
 
     /**
-     * Client data passed to DebugBreakForCommand function. The
-     * debugger takes ownership of the data and will delete it even if
-     * there is no message handler.
+     * This is now a dummy that returns nullptr.
      */
     virtual ClientData* GetClientData() const = 0;
 
@@ -132,23 +130,18 @@ class V8_EXPORT Debug {
    *
    * \param event_details object providing information about the debug event
    *
-   * A EventCallback2 does not take possession of the event data,
+   * A EventCallback does not take possession of the event data,
    * and must not rely on the data persisting after the handler returns.
    */
   typedef void (*EventCallback)(const EventDetails& event_details);
 
   /**
-   * Debug message callback function.
-   *
-   * \param message the debug message handler message object
-   *
-   * A MessageHandler does not take possession of the message data,
-   * and must not rely on the data persisting after the handler returns.
+   * This is now a no-op.
    */
   typedef void (*MessageHandler)(const Message& message);
 
   /**
-   * Callback function for the host to ensure debug messages are processed.
+   * This is now a no-op.
    */
   typedef void (*DebugMessageDispatchHandler)();
 
@@ -167,11 +160,12 @@ class V8_EXPORT Debug {
   V8_DEPRECATED("No longer supported",
                 static bool CheckDebugBreak(Isolate* isolate));
 
-  // Message based interface. The message protocol is JSON.
+  // This is now a no-op.
   V8_DEPRECATED("No longer supported",
                 static void SetMessageHandler(Isolate* isolate,
                                               MessageHandler handler));
 
+  // This is now a no-op.
   V8_DEPRECATED("No longer supported",
                 static void SendCommand(Isolate* isolate,
                                         const uint16_t* command, int length,
@@ -207,37 +201,7 @@ class V8_EXPORT Debug {
                 static MaybeLocal<Value> GetMirror(Local<Context> context,
                                                    v8::Local<v8::Value> obj));
 
-  /**
-   * Makes V8 process all pending debug messages.
-   *
-   * From V8 point of view all debug messages come asynchronously (e.g. from
-   * remote debugger) but they all must be handled synchronously: V8 cannot
-   * do 2 things at one time so normal script execution must be interrupted
-   * for a while.
-   *
-   * Generally when message arrives V8 may be in one of 3 states:
-   * 1. V8 is running script; V8 will automatically interrupt and process all
-   * pending messages;
-   * 2. V8 is suspended on debug breakpoint; in this state V8 is dedicated
-   * to reading and processing debug messages;
-   * 3. V8 is not running at all or has called some long-working C++ function;
-   * by default it means that processing of all debug messages will be deferred
-   * until V8 gets control again; however, embedding application may improve
-   * this by manually calling this method.
-   *
-   * Technically this method in many senses is equivalent to executing empty
-   * script:
-   * 1. It does nothing except for processing all pending debug messages.
-   * 2. It should be invoked with the same precautions and from the same context
-   * as V8 script would be invoked from, because:
-   *   a. with "evaluate" command it can do whatever normal script can do,
-   *   including all native calls;
-   *   b. no other thread should call V8 while this method is running
-   *   (v8::Locker may be used here).
-   *
-   * "Evaluate" debug command behavior currently is not specified in scope
-   * of this method.
-   */
+  // This is now a no-op.
   V8_DEPRECATED("No longer supported",
                 static void ProcessDebugMessages(Isolate* isolate));