Added following dart API changes to enable more efficient access based

runtime/include/dart_api.h

 /*
  * 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.
  */
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 1505 matching lines @@
  * Gets the storage size in bytes of a String.
  *
  * \param str A String.
  * \param length Returns the storage size in bytes of the String.
  *  This is the size in bytes needed to store the String.
  *
  * \return A valid handle if no error occurs during the operation.
  */
 DART_EXPORT Dart_Handle Dart_StringStorageSize(Dart_Handle str, intptr_t* size);
 
-
 /**
  * Converts a String into an ExternalString.
  * The original object is morphed into an external string object.
  *
  * \param array External space into which the string data will be
  *   copied into. This must not move.
  * \param length The size in bytes of the provided external space (array).
  * \param peer An external pointer to associate with this string.
  * \param cback A callback to be called when this string is finalized.
  *
@@ skipping 10 matching lines @@
  *  void* data = malloc(size);
  *  result = Dart_MakeExternalString(str, data, size, NULL, NULL);
  *
  */
 DART_EXPORT Dart_Handle Dart_MakeExternalString(Dart_Handle str,
                                                 void* array,
                                                 intptr_t length,
                                                 void* peer,
                                                 Dart_PeerFinalizer cback);
 
+/**
+ * Retrieves some properties associated with a String.
+ * Properties retrieved are:
+ * - character size of the string (one or two byte)
+ * - length of the string
+ * - peer pointer of string if it is an external string.
+ * \param str A String.
+ * \param char_size Returns the character size of the String.
+ * \param str_len Returns the length of the String.
+ * \param peer Returns the peer pointer if the String is an external String.
+ * \return Success if no error occurs. Otherwise returns
+ *   an error handle.
+ */
+DART_EXPORT Dart_Handle Dart_StringGetProperties(Dart_Handle str,
+                                                 intptr_t* char_size,
+                                                 intptr_t* str_len,
+                                                 void** peer);
 
 /*
  * =====
  * Lists
  * =====
  */
 
 /**
  * Returns a List of the desired length.
  *
@@ skipping 408 matching lines @@
                                                       int fld_index,
                                                       intptr_t* value);
 
 /**
  * Gets the native field of the receiver.
  */
 DART_EXPORT Dart_Handle Dart_GetNativeReceiver(Dart_NativeArguments args,
                                                intptr_t* value);
 
 /**
+ * Gets a string native argument at some index.
+ * \param args Native arguments structure.
+ * \param arg_index Index of the desired argument in the structure above.
+ * \param peer Returns the peer pointer if the String is an external String.
+ * \return the String object if no error occurs. Otherwise returns
+ *   an error handle.
+ */
+DART_EXPORT Dart_Handle Dart_GetNativeStringArgument(Dart_NativeArguments args,
+                                                     int arg_index,
+                                                     void** peer);
+
+/**
  * Sets the return value for a native function.
  */
 DART_EXPORT void Dart_SetReturnValue(Dart_NativeArguments args,
                                      Dart_Handle retval);
 
+DART_EXPORT void Dart_SetWeakHandleReturnValue(Dart_NativeArguments args,
+                                               Dart_WeakPersistentHandle rval);
+
 DART_EXPORT void Dart_SetBooleanReturnValue(Dart_NativeArguments args,
                                             bool retval);
 
 DART_EXPORT void Dart_SetIntegerReturnValue(Dart_NativeArguments args,
                                             intptr_t retval);
 
 DART_EXPORT void Dart_SetDoubleReturnValue(Dart_NativeArguments args,
                                            double retval);
 
 /**
@@ skipping 222 matching lines @@
  *
  * \param object An object.
  * \param peer A value to store in the peer field.
  *
  * \return Returns an error if 'object' is a subtype of Null, num, or
  *   bool.
  */
 DART_EXPORT Dart_Handle Dart_SetPeer(Dart_Handle object, void* peer);
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */