Remember when an isolate was paused and subtly display it in Obseravatory

runtime/vm/message_handler.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_MESSAGE_HANDLER_H_
 #define VM_MESSAGE_HANDLER_H_
 
 #include "vm/isolate.h"
 #include "vm/message.h"
 #include "vm/os_thread.h"
@@ skipping 78 matching lines @@
   }
 
   void set_pause_on_exit(bool pause_on_exit) {
     pause_on_exit_ = pause_on_exit;
   }
 
   bool paused_on_exit() const {
     return paused_on_exit_;
   }
 
+  // Timestamp of the paused on start or paused on exit.
+  int64_t paused_timestamp() const {
+    return paused_timestamp_;
+  }
+
   class AcquiredQueues : public ValueObject {
    public:
     AcquiredQueues();
 
     ~AcquiredQueues();
 
     MessageQueue* queue() {
       if (handler_ == NULL) {
         return NULL;
       }
@@ skipping 91 matching lines @@
   MessageQueue* oob_queue_;
   // This flag is not thread safe and can only reliably be accessed on a single
   // thread.
   bool oob_message_handling_allowed_;
   intptr_t live_ports_;  // The number of open ports, including control ports.
   intptr_t paused_;  // The number of pause messages received.
   bool pause_on_start_;
   bool pause_on_exit_;
   bool paused_on_start_;
   bool paused_on_exit_;
+  int64_t paused_timestamp_;
   ThreadPool* pool_;
   ThreadPool::Task* task_;
   StartCallback start_callback_;
   EndCallback end_callback_;
   CallbackData callback_data_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageHandler);
 };
 
 }  // namespace dart
 
 #endif  // VM_MESSAGE_HANDLER_H_