Last snapshot bits to get working precompiled hello_world on x64.

runtime/bin/main.cc

Index: runtime/bin/main.cc
diff --git a/runtime/bin/main.cc b/runtime/bin/main.cc
index 702a8a2f50ded29165b6549fbe47f8a8cb7bc8d0..7e111637a5f7012443046587ffd61bdee81670b7 100644
--- a/runtime/bin/main.cc
+++ b/runtime/bin/main.cc
@@ -751,22 +751,24 @@ static Dart_Isolate CreateIsolateAndSetupHelper(const char* script_uri,
   result = Dart_SetEnvironmentCallback(EnvironmentCallback);
   CHECK_RESULT(result);
 
-  // Load the script.
-  result = DartUtils::LoadScript(script_uri, builtin_lib);
-  CHECK_RESULT(result);
+  if (!has_run_precompiled_snapshot) {
+    // Load the script.
+    result = DartUtils::LoadScript(script_uri, builtin_lib);
+    CHECK_RESULT(result);
 
-  // Run event-loop and wait for script loading to complete.
-  result = Dart_RunLoop();
-  CHECK_RESULT(result);
+    // Run event-loop and wait for script loading to complete.
+    result = Dart_RunLoop();
+    CHECK_RESULT(result);
 
-  if (isolate_data->load_async_id >= 0) {
-    Dart_TimelineAsyncEnd("LoadScript", isolate_data->load_async_id);
-  }
+    if (isolate_data->load_async_id >= 0) {
+      Dart_TimelineAsyncEnd("LoadScript", isolate_data->load_async_id);
+    }
 
-  Platform::SetPackageRoot(package_root);
+    Platform::SetPackageRoot(package_root);
 
-  result = DartUtils::SetupIOLibrary(script_uri);
-  CHECK_RESULT(result);
+    result = DartUtils::SetupIOLibrary(script_uri);
+    CHECK_RESULT(result);
+  }
 
   // Make the isolate runnable so that it is ready to handle messages.
   Dart_ExitScope();