[Chromecast] Turn CastContentWindow into an abstract interface.

chromecast/browser/test/cast_browser_test.cc

Index: chromecast/browser/test/cast_browser_test.cc
diff --git a/chromecast/browser/test/cast_browser_test.cc b/chromecast/browser/test/cast_browser_test.cc
index 7d950e7d5dd2c1942736502feeff075cd1ed5314..4ec04f7e1f5a5138d81afc16b415b927ab8bb357 100644
--- a/chromecast/browser/test/cast_browser_test.cc
+++ b/chromecast/browser/test/cast_browser_test.cc
@@ -60,11 +60,11 @@ void CastBrowserTest::RunTestOnMainThreadLoop() {
 }
 
 content::WebContents* CastBrowserTest::NavigateToURL(const GURL& url) {
-  window_ = base::MakeUnique<CastContentWindow>();
+  window_ = CastContentWindow::Create(this);
 
   web_contents_ = window_->CreateWebContents(
       CastBrowserProcess::GetInstance()->browser_context());
-  window_->CreateWindowTree(web_contents_.get());
+  window_->ShowWebContents(web_contents_.get());
   content::WaitForLoadStop(web_contents_.get());
 
   content::TestNavigationObserver same_tab_observer(web_contents_.get(), 1);
@@ -77,5 +77,9 @@ content::WebContents* CastBrowserTest::NavigateToURL(const GURL& url) {
   return web_contents_.get();
 }
 
+void CastBrowserTest::OnWindowDestroyed() {}
+
+void CastBrowserTest::OnKeyEvent(const ui::KeyEvent& key_event) {}
+
 }  // namespace shell
 }  // namespace chromecast