Add trace_service_pause_events flag and related tracing

runtime/vm/service.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/service.h"
 
 #include "include/dart_api.h"
 #include "platform/globals.h"
 
 #include "vm/compiler.h"
@@ skipping 14 matching lines @@
 #include "vm/port.h"
 #include "vm/profiler.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/version.h"
 
 
 namespace dart {
 
 DEFINE_FLAG(bool, trace_service, false, "Trace VM service requests.");
+DEFINE_FLAG(bool, trace_service_pause_events, false,
+            "Trace VM service isolate pause events.");
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, enable_asserts);
 
 struct ResourcesEntry {
   const char* path_;
   const char* resource_;
   int length_;
 };
 
 extern ResourcesEntry __service_resources_[];
@@ skipping 1940 matching lines @@
   while (current != NULL) {
     if (strcmp(name, current->name()) == 0) {
       return current;
     }
     current = current->next();
   }
   return NULL;
 }
 
 }  // namespace dart