Add access to the isolate package-root/package-map in Platform.

runtime/bin/platform.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 "bin/platform.h"
 
 #include "include/dart_api.h"
 
 #include "bin/file.h"
 #include "bin/utils.h"
@@ skipping 58 matching lines @@
     Dart_Handle str = DartUtils::NewString(argv[i]);
     Dart_Handle error = Dart_ListSetAt(result, i - 1, str);
     if (Dart_IsError(error)) {
       Dart_PropagateError(error);
     }
   }
   Dart_SetReturnValue(args, result);
 }
 
 
-void FUNCTION_NAME(Platform_PackageRoot)(Dart_NativeArguments args) {
-  const char* package_root = Platform::GetPackageRoot();
-  if (package_root == NULL) {
-    package_root = "";
-  }
-  Dart_SetReturnValue(args, Dart_NewStringFromCString(package_root));
-}
-
-
 void FUNCTION_NAME(Platform_Environment)(Dart_NativeArguments args) {
   intptr_t count = 0;
   char** env = Platform::Environment(&count);
   if (env == NULL) {
     OSError error(-1,
                   "Failed to retrieve environment variables.",
                   OSError::kUnknown);
     Dart_SetReturnValue(args, DartUtils::NewDartOSError(&error));
   } else {
     Dart_Handle result = Dart_NewList(count);
@@ skipping 18 matching lines @@
   }
 }
 
 
 void FUNCTION_NAME(Platform_GetVersion)(Dart_NativeArguments args) {
   Dart_SetReturnValue(args, Dart_NewStringFromCString(Dart_VersionString()));
 }
 
 }  // namespace bin
 }  // namespace dart