headless: Add support for net logging

headless/lib/browser/headless_browser_main_parts.cc

Index: headless/lib/browser/headless_browser_main_parts.cc
diff --git a/headless/lib/browser/headless_browser_main_parts.cc b/headless/lib/browser/headless_browser_main_parts.cc
index 2ae52c3cc31eacb067aa583a6c8daf8d8ef6817f..6423a44113cbf75438d41e2e44fea22eb09aee35 100644
--- a/headless/lib/browser/headless_browser_main_parts.cc
+++ b/headless/lib/browser/headless_browser_main_parts.cc
@@ -4,9 +4,12 @@
 
 #include "headless/lib/browser/headless_browser_main_parts.h"
 
+#include "base/command_line.h"
+#include "content/public/common/content_switches.h"
 #include "headless/lib/browser/headless_browser_context_impl.h"
 #include "headless/lib/browser/headless_browser_impl.h"
 #include "headless/lib/browser/headless_devtools.h"
+#include "headless/lib/browser/headless_net_log.h"
 #include "headless/lib/browser/headless_screen.h"
 
 namespace headless {
@@ -18,6 +21,14 @@ HeadlessBrowserMainParts::HeadlessBrowserMainParts(HeadlessBrowserImpl* browser)
 HeadlessBrowserMainParts::~HeadlessBrowserMainParts() {}
 
 void HeadlessBrowserMainParts::PreMainMessageLoopRun() {
+  const base::CommandLine* command_line =
+      base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kLogNetLog)) {
+    base::FilePath log_path =
+        command_line->GetSwitchValuePath(switches::kLogNetLog);
+    net_log_.reset(new HeadlessNetLog(log_path));
+  }
+
   if (browser_->options()->devtools_endpoint.address().IsValid()) {
     StartLocalDevToolsHttpHandler(browser_->options());
     devtools_http_handler_started_ = true;