add print to pdf for headless

headless/lib/headless_content_main_delegate.cc

Index: headless/lib/headless_content_main_delegate.cc
diff --git a/headless/lib/headless_content_main_delegate.cc b/headless/lib/headless_content_main_delegate.cc
index 561f14be35cfa75812c88ee6cc6c9c45f652ab62..ba18858a7f37f868e9f8fe0f97ca619b992520fa 100644
--- a/headless/lib/headless_content_main_delegate.cc
+++ b/headless/lib/headless_content_main_delegate.cc
@@ -20,6 +20,7 @@
 #include "headless/lib/browser/headless_content_browser_client.h"
 #include "headless/lib/headless_crash_reporter_client.h"
 #include "headless/lib/headless_macros.h"
+#include "headless/lib/renderer/headless_content_renderer_client.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/gfx/switches.h"
@@ -270,4 +271,10 @@ HeadlessContentMainDelegate::CreateContentBrowserClient() {
   return browser_client_.get();
 }
 
+content::ContentRendererClient*
+HeadlessContentMainDelegate::CreateContentRendererClient() {
+  renderer_client_.reset(new HeadlessContentRendererClient);

[Lei Zhang, 2017/03/29 01:38:03]

nit: foo.reset(new Foo(bar)) -> foo = base::MakeUnique<Foo>(bar)

[jzfeng, 2017/03/29 03:50:13]

Done.

+  return renderer_client_.get();
+}
+
 }  // namespace headless