Infrastructure for reading V8's initial snapshot from external files

mojo/apps/js/standalone_main.cc

Index: mojo/apps/js/standalone_main.cc
diff --git a/mojo/apps/js/standalone_main.cc b/mojo/apps/js/standalone_main.cc
index efdfcb872f448cab69c87d90b8aa8ff71a57f980..c5d0c17359f2c107ec9a35d397508e8560b4d7a5 100644
--- a/mojo/apps/js/standalone_main.cc
+++ b/mojo/apps/js/standalone_main.cc
@@ -11,6 +11,10 @@
 #include "mojo/public/cpp/application/application_delegate.h"
 #include "mojo/public/cpp/application/application_impl.h"
 
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+#include "gin/public/isolate_holder.h"
+#endif
+
 namespace mojo {
 namespace apps {
 
@@ -49,6 +53,9 @@ class StandaloneApplicationDelegateImpl : public ApplicationDelegateImpl {
 
 MojoResult MojoMain(MojoHandle shell_handle) {
   base::i18n::InitializeICU();
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+  gin::IsolateHolder::LoadV8Snapshot();
+#endif
   mojo::ApplicationRunnerChromium runner(
       new mojo::apps::StandaloneApplicationDelegateImpl());
   return runner.Run(shell_handle);