Allow for embedder provided service request handlers

runtime/platform/json.cc

 // Copyright (c) 2012, 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/json.h"
 
 #include "platform/assert.h"
 #include "platform/globals.h"
 #include "platform/utils.h"
 #include "vm/os.h"
@@ skipping 492 matching lines @@
   buf_ = NULL;
 }
 
 
 void TextBuffer::Clear() {
   msg_len_ = 0;
   buf_[0] = '\0';
 }
 
 
+const char* TextBuffer::Steal() {
+  const char* r = buf_;
+  buf_ = NULL;
+  buf_size_ = 0;
+  msg_len_ = 0;
+  return r;
+}
+
+
 void TextBuffer::AddChar(char ch) {
   EnsureCapacity(sizeof(ch));
   buf_[msg_len_] = ch;
   msg_len_++;
   buf_[msg_len_] = '\0';
 }
 
 
 void TextBuffer::AddUTF8(uint32_t ch) {
   static const uint32_t kMaxOneByteChar   = 0x7F;
@@ skipping 120 matching lines @@
     // the debugger front-end.
     intptr_t new_size = buf_size_ + len + kBufferSpareCapacity;
     char* new_buf = reinterpret_cast<char*>(realloc(buf_, new_size));
     ASSERT(new_buf != NULL);
     buf_ = new_buf;
     buf_size_ = new_size;
   }
 }
 
 }  // namespace dart