Chromecast: use CastContent{Browser,Renderer}Client as a base class.

chromecast/app/cast_main_delegate.cc

Index: chromecast/app/cast_main_delegate.cc
diff --git a/chromecast/app/cast_main_delegate.cc b/chromecast/app/cast_main_delegate.cc
index 58c7507eaf3bbe435ad88e958f3b8d9ddc31d273..68c8f376ca74cc2a05e0ba5cca64ed590f2cb509 100644
--- a/chromecast/app/cast_main_delegate.cc
+++ b/chromecast/app/cast_main_delegate.cc
@@ -150,13 +150,13 @@ void CastMainDelegate::InitializeResourceBundle() {
 }
 
 content::ContentBrowserClient* CastMainDelegate::CreateContentBrowserClient() {
-  browser_client_.reset(new CastContentBrowserClient);
+  browser_client_.reset(PlatformCreateCastBrowserClient());
   return browser_client_.get();
 }
 
 content::ContentRendererClient*
 CastMainDelegate::CreateContentRendererClient() {
-  renderer_client_.reset(new CastContentRendererClient);
+  renderer_client_.reset(PlatformCreateCastRendererClient());
   return renderer_client_.get();
 }