headless: Add support for net logging

headless/lib/browser/headless_browser_main_parts.h

Index: headless/lib/browser/headless_browser_main_parts.h
diff --git a/headless/lib/browser/headless_browser_main_parts.h b/headless/lib/browser/headless_browser_main_parts.h
index 0bf44ee55d472aa31d3905585aee66f70a8b23db..0b8d81f84d73fbc115c7161966003930fed886ef 100644
--- a/headless/lib/browser/headless_browser_main_parts.h
+++ b/headless/lib/browser/headless_browser_main_parts.h
@@ -7,11 +7,13 @@
 
 #include <memory>
 
+#include "base/files/file_path.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "headless/public/headless_browser.h"
 
 namespace headless {
 
+class HeadlessNetLog;
 class HeadlessBrowserImpl;
 
 class HeadlessBrowserMainParts : public content::BrowserMainParts {
@@ -26,10 +28,13 @@ class HeadlessBrowserMainParts : public content::BrowserMainParts {
   void PreMainMessageLoopStart() override;
 #endif
 
+  HeadlessNetLog* net_log() const { return net_log_.get(); }
+
  private:
   HeadlessBrowserImpl* browser_;  // Not owned.
 
   bool devtools_http_handler_started_;
+  std::unique_ptr<HeadlessNetLog> net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(HeadlessBrowserMainParts);
 };