Infrastructure for reading V8's initial snapshot from external files

mojo/apps/js/main.cc

Index: mojo/apps/js/main.cc
diff --git a/mojo/apps/js/main.cc b/mojo/apps/js/main.cc
index 5ecf47d5d061ffb049f35c4d7a2df9ab3e1a2bb3..e57b89bc865270f929d85387f3ed81df993f0b2d 100644
--- a/mojo/apps/js/main.cc
+++ b/mojo/apps/js/main.cc
@@ -3,12 +3,18 @@
 // found in the LICENSE file.
 
 #include "base/i18n/icu_util.h"
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+#include "gin/public/isolate_holder.h"
+#endif // V8_USE_EXTERNAL_STARTUP_DATA
 #include "mojo/application/application_runner_chromium.h"
 #include "mojo/apps/js/application_delegate_impl.h"
 #include "mojo/public/c/system/main.h"
 
 MojoResult MojoMain(MojoHandle shell_handle) {
   base::i18n::InitializeICU();
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+  gin::IsolateHolder::LoadV8Snapshot();
+#endif // V8_USE_EXTERNAL_STARTUP_DATA
   mojo::ApplicationRunnerChromium runner(
       new mojo::apps::ApplicationDelegateImpl());
   return runner.Run(shell_handle);