Add timeline stream control and trace retrieval to the dart embedder api.

runtime/vm/json_stream.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 "platform/assert.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/json_stream.h"
 #include "vm/message.h"
@@ skipping 516 matching lines @@
   intptr_t len2 = OS::VSNPrint(p, len+1, format, args);
   va_end(args);
   ASSERT(len == len2);
   buffer_.AddChar('"');
   AddEscapedUTF8String(p);
   buffer_.AddChar('"');
   free(p);
 }
 
 
+void JSONStream::Steal(const char** buffer, intptr_t* buffer_length) {
+  ASSERT(buffer != NULL);
+  ASSERT(buffer_length != NULL);
+  *buffer_length = buffer_.length();
+  *buffer = buffer_.Steal();
+}
+
+
 void JSONStream::set_reply_port(Dart_Port port) {
   reply_port_ = port;
 }
 
 
 void JSONStream::SetParams(const char** param_keys,
                            const char** param_values,
                            intptr_t num_params) {
   param_keys_ = param_keys;
   param_values_ = param_values;
@@ skipping 153 matching lines @@
   intptr_t len2 = OS::VSNPrint(p, len+1, format, args);
   va_end(args);
   ASSERT(len == len2);
   stream_->buffer_.AddChar('"');
   stream_->AddEscapedUTF8String(p);
   stream_->buffer_.AddChar('"');
   free(p);
 }
 
 }  // namespace dart