- Implement a first cut for const String.env in the VM to allow

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
===================================================================
--- runtime/include/dart_api.h	(revision 28841)
+++ runtime/include/dart_api.h	(working copy)
@@ -1476,7 +1476,7 @@
 /**
  * Gets the data corresponding to the string object. This function returns
  * the data only for Latin-1 (ISO-8859-1) string objects. For all other
- * string objects it return and error.
+ * string objects it returns an error.
  *
  * \param str A string.
  * \param latin1_array An array allocated by the caller, used to return
@@ -2120,6 +2120,29 @@
 
 
 /*
+ * ===========
+ * Environment
+ * ===========
+ */
+
+typedef enum {
+  kStringEnvironment = 0,
+  kIntegerEnvironment,
+  kBoolEnvironment
+} Dart_EnvironmentType;
+
+/* TODO(iposva): Document. */
+typedef Dart_Handle (*Dart_EnvironmentCallback)(Dart_EnvironmentType type,
+                                                Dart_Handle name);
+
+/**
+ * Sets the configuration callback for the current isolate. This callback is
+ * used to lookup configuration values by name in the current environment.
+ */
+DART_EXPORT Dart_Handle Dart_SetEnvironmentCallback(
+    Dart_EnvironmentCallback callback);
+
+/*
  * =====================
  * Scripts and Libraries
  * =====================