Introduce Dart_SetVMFlags API function.

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
===================================================================
--- runtime/include/dart_api.h	(revision 1859)
+++ runtime/include/dart_api.h	(working copy)
@@ -247,19 +247,24 @@
 // TODO(turnidge): Should we separate the two return values?
 
 /**
- * Initializes the VM with the given commmand line flags.
+ * Initializes the VM.
  *
- * \param argc The length of the arguments array.
- * \param argv An array of arguments.
  * \param callback A function to be called during isolate creation.
  *   See Dart_IsolateInitCallback.
  *
  * \return True if initialization is successful.
  */
-DART_EXPORT bool Dart_Initialize(int argc, const char** argv,
-                                 Dart_IsolateInitCallback callback);
+DART_EXPORT bool Dart_Initialize(Dart_IsolateInitCallback callback);
 
 /**
+ * Sets command line flags.
+ *
+ * \param argc The length of the arguments array.
+ * \param argv An array of arguments.
+ */
+DART_EXPORT void Dart_SetVMFlags(int argc, const char** argv);
+
+/**
  * Returns true if the named VM flag is set.
  */
 DART_EXPORT bool Dart_IsVMFlagSet(const char* flag_name);