[Chromecast] Turn CastContentWindow into an abstract interface.

chromecast/browser/service/cast_service_simple.cc

Index: chromecast/browser/service/cast_service_simple.cc
diff --git a/chromecast/browser/service/cast_service_simple.cc b/chromecast/browser/service/cast_service_simple.cc
index 25ebc50a4aeb0e60ebf4742f35d29699ffd7fdae..1721a971df7c25870dca20ac7f97d630311ab59f 100644
--- a/chromecast/browser/service/cast_service_simple.cc
+++ b/chromecast/browser/service/cast_service_simple.cc
@@ -6,6 +6,7 @@
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
+#include "base/memory/ptr_util.h"
 #include "chromecast/browser/cast_content_window.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
@@ -51,9 +52,9 @@ void CastServiceSimple::FinalizeInternal() {
 }
 
 void CastServiceSimple::StartInternal() {
-  window_.reset(new CastContentWindow);
+  window_ = CastContentWindow::Create(nullptr);
   web_contents_ = window_->CreateWebContents(browser_context());
-  window_->CreateWindowTree(web_contents_.get());
+  window_->ShowWebContents(web_contents_.get());
 
   web_contents_->GetController().LoadURL(startup_url_, content::Referrer(),
                                          ui::PAGE_TRANSITION_TYPED,