Fix to asiva's code review comments on TBR Cl.

runtime/include/dart_debugger_api.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 INCLUDE_DART_DEBUGGER_API_H_
 #define INCLUDE_DART_DEBUGGER_API_H_
 
 #include "include/dart_api.h"
 
 typedef struct _Dart_Breakpoint* Dart_Breakpoint;
@@ skipping 582 matching lines @@
  * Returns a handle to the library \library_id.
  *
  * Requires there to be a current isolate.
  *
  * \return A library handle if the id is valid.
  */
 DART_EXPORT Dart_Handle Dart_GetLibraryFromId(intptr_t library_id);
 
 
 /**
+ * Returns in \library_id the library id of the given \library.
+ *
+ * \return A valid handle if no error occurs during the operation.
+ */
+DART_EXPORT Dart_Handle Dart_LibraryId(Dart_Handle library,
+                                       intptr_t* library_id);
+
+
+/**
  * Returns an array containing all variable names and values of
  * the given library \library_id.
  *
  * Requires there to be a current isolate.
  *
  * \return A handle to an array containing variable names and
  * corresponding values. The array is empty if the library has
  * no variables. If non-empty, variable names are at array offsets 2*n,
  * values at offset 2*n+1. Variable values may also be a handle to an
  * error object if an error was encountered evaluating the value.
@@ skipping 53 matching lines @@
  * \param request A REST-like string, which uses '/' to separate
  *     parameters. The first parameter is always the status type.
  *
  * \return The requested status as a JSON formatted string, with the
  *     contents defined by the status plug-in. The caller is responsible
  *     for freeing this string.
  */
 DART_EXPORT char* Dart_GetVmStatus(const char* request);
 
 #endif  // INCLUDE_DART_DEBUGGER_API_H_