[Chromecast] Add proxy server support to chromecast

chromecast/browser/url_request_context_factory.h

Index: chromecast/browser/url_request_context_factory.h
diff --git a/chromecast/browser/url_request_context_factory.h b/chromecast/browser/url_request_context_factory.h
index 1b2396eb37cf4447c0bc5f21963a2339bb3dc47b..d2f5e9bf8360f811ddbec30fc76ef0aa2e501651 100644
--- a/chromecast/browser/url_request_context_factory.h
+++ b/chromecast/browser/url_request_context_factory.h
@@ -9,6 +9,8 @@
 #include "content/public/browser/content_browser_client.h"
 #include "net/http/http_network_session.h"
 
+class PrefProxyConfigTracker;
+
 namespace net {
 class CookieStore;
 class HttpTransactionFactory;
@@ -124,6 +126,8 @@ class URLRequestContextFactory {
   bool media_dependencies_initialized_;
   std::unique_ptr<net::HttpTransactionFactory> media_transaction_factory_;
 
+  std::unique_ptr<PrefProxyConfigTracker> pref_proxy_config_tracker_impl_;
+
   // Determines if QUIC is enabled for a URLContextGetter when it is created.
   // QUIC can be disabled at runtime by calling DisableQuic() above.
   // Only accessed on content::BrowserThread::IO thread.