Refactor client cert private key handling.

chromecast/browser/cast_network_delegate.h

Index: chromecast/browser/cast_network_delegate.h
diff --git a/chromecast/browser/cast_network_delegate.h b/chromecast/browser/cast_network_delegate.h
index c573a6c6baf01b3575284a0b1ecbfefd23ca1164..bfe4c6919703d1363f719c887a4e522cc6628c49 100644
--- a/chromecast/browser/cast_network_delegate.h
+++ b/chromecast/browser/cast_network_delegate.h
@@ -9,6 +9,7 @@
 #include "net/base/network_delegate_impl.h"
 
 namespace net {
+class SSLPrivateKey;
 class X509Certificate;
 }
 
@@ -19,6 +20,7 @@ class CastNetworkDelegate : public net::NetworkDelegateImpl {
  public:
   static CastNetworkDelegate* Create();
   static net::X509Certificate* DeviceCert();
+  static net::SSLPrivateKey* DeviceKey();
 
   CastNetworkDelegate();
   ~CastNetworkDelegate() override;