Remove Dart_GetScriptSource as it is not used anywhere.

runtime/vm/debugger_api_impl.cc

Index: runtime/vm/debugger_api_impl.cc
===================================================================
--- runtime/vm/debugger_api_impl.cc	(revision 19995)
+++ runtime/vm/debugger_api_impl.cc	(working copy)
@@ -568,31 +568,6 @@
 }
 
 
-DART_EXPORT Dart_Handle Dart_GetScriptSource(
-                            Dart_Handle library_url_in,
-                            Dart_Handle script_url_in) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  UNWRAP_AND_CHECK_PARAM(String, library_url, library_url_in);
-  UNWRAP_AND_CHECK_PARAM(String, script_url, script_url_in);
-
-  const Library& library = Library::Handle(Library::LookupLibrary(library_url));
-  if (library.IsNull()) {
-    return Api::NewError("%s: library '%s' not found",
-                         CURRENT_FUNC, library_url.ToCString());
-  }
-
-  const Script& script = Script::Handle(library.LookupScript(script_url));
-  if (script.IsNull()) {
-    return Api::NewError("%s: script '%s' not found in library '%s'",
-                         CURRENT_FUNC, script_url.ToCString(),
-                         library_url.ToCString());
-  }
-
-  return Api::NewHandle(isolate, script.Source());
-}
-
-
 DART_EXPORT Dart_Handle Dart_GetScriptURLs(Dart_Handle library_url_in) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);