Fix DCHECH errors on Windows

headless/public/headless_browser.h

Index: headless/public/headless_browser.h
diff --git a/headless/public/headless_browser.h b/headless/public/headless_browser.h
index b57c21aac9214912e77db31c929e8dfd6916a9d5..fdc65a54fc6a1b208965640f9b7de479c5e676c4 100644
--- a/headless/public/headless_browser.h
+++ b/headless/public/headless_browser.h
@@ -226,6 +226,7 @@ class HEADLESS_EXPORT HeadlessBrowser::Options::Builder {
   DISALLOW_COPY_AND_ASSIGN(Builder);
 };
 
+#if !defined(OS_WIN)
 // The headless browser may need to create child processes (e.g., a renderer
 // which runs web content). This is done by re-executing the parent process as
 // a zygote[1] and forking each child process from that zygote.
@@ -245,9 +246,17 @@ class HEADLESS_EXPORT HeadlessBrowser::Options::Builder {
 //
 // [1]
 // https://chromium.googlesource.com/chromium/src/+/master/docs/linux_zygote.md
-#if !defined(OS_WIN)
 HEADLESS_EXPORT void RunChildProcessIfNeeded(int argc, const char** argv);
-#endif
+#else
+// In Windows, the headless browser may need to create child processes. This is
+// done by re-executing the parent process which may have been initialized with
+// different libraries (e.g. child_dll). In this case, the embedder has to pass
+// the appropiate HINSTANCE and initalization sandbox_info to properly launch
+// the child process.
+HEADLESS_EXPORT void RunChildProcessIfNeeded(
+    HINSTANCE instance,
+    sandbox::SandboxInterfaceInfo* sandbox_info);
+#endif  // !defined(OS_WIN)
 
 // Main entry point for running the headless browser. This function constructs
 // the headless browser instance, passing it to the given