initial version of the headless download manager delegate

headless/lib/browser/headless_browser_context_impl.h

Index: headless/lib/browser/headless_browser_context_impl.h
diff --git a/headless/lib/browser/headless_browser_context_impl.h b/headless/lib/browser/headless_browser_context_impl.h
index b06766a4f92ada2ec78a5a8987df9072e128e39b..8bc04eb8f613e4f7600c5992befeac70aee0c537 100644
--- a/headless/lib/browser/headless_browser_context_impl.h
+++ b/headless/lib/browser/headless_browser_context_impl.h
@@ -18,14 +18,17 @@
 #include "headless/lib/browser/headless_url_request_context_getter.h"
 #include "headless/public/headless_browser.h"
 #include "headless/public/headless_browser_context.h"
+#include "headless/public/headless_export.h"
 
 namespace headless {
 class HeadlessBrowserImpl;
+class HeadlessDownloadManagerDelegate;
 class HeadlessResourceContext;
 class HeadlessWebContentsImpl;
 
-class HeadlessBrowserContextImpl : public HeadlessBrowserContext,
-                                   public content::BrowserContext {
+class HEADLESS_EXPORT HeadlessBrowserContextImpl
+    : public HeadlessBrowserContext,
+      public content::BrowserContext {
  public:
   ~HeadlessBrowserContextImpl() override;
 
@@ -105,6 +108,7 @@ class HeadlessBrowserContextImpl : public HeadlessBrowserContext,
   HeadlessBrowserImpl* browser_;  // Not owned.
   std::unique_ptr<HeadlessBrowserContextOptions> context_options_;
   std::unique_ptr<HeadlessResourceContext> resource_context_;
+  std::unique_ptr<HeadlessDownloadManagerDelegate> download_manager_delegate_;
   base::FilePath path_;
 
   std::unordered_map<std::string, std::unique_ptr<HeadlessWebContents>>