Land https://codereview.chromium.org/2662393002 for Jason.

runtime/bin/embedded_dart_io.h

Index: runtime/bin/embedded_dart_io.h
diff --git a/runtime/bin/embedded_dart_io.h b/runtime/bin/embedded_dart_io.h
index 84f5aa4af3ee22c395ad6185c44b8af38546ac3e..9ce24b9eea219e93cae04098912b658722af1367 100644
--- a/runtime/bin/embedded_dart_io.h
+++ b/runtime/bin/embedded_dart_io.h
@@ -27,6 +27,12 @@ bool ShouldCaptureStdout();
 // Should Stderr events be captured?
 bool ShouldCaptureStderr();
 
+// Set the executable name used by Platform.executable.
+void SetExecutableName(const char* executable_name);
+
+// Set the arguments used by Platform.executableArguments.
+void SetExecutableArguments(int script_index, char** argv);
+
 }  // namespace bin
 }  // namespace dart