V2 app support step2 : Use NativeAppWindow for Activity's window.

athena/content/shell/shell_app_activity.cc

Index: athena/content/shell/shell_app_activity.cc
diff --git a/athena/content/shell/shell_app_activity.cc b/athena/content/shell/shell_app_activity.cc
index 7e414e7ef59cdbb40d1d4ce7870b88b7f4ae74ce..d8a507737735c53a30fb4767758daef5adccce2b 100644
--- a/athena/content/shell/shell_app_activity.cc
+++ b/athena/content/shell/shell_app_activity.cc
@@ -4,7 +4,9 @@
 
 #include "athena/content/shell/shell_app_activity.h"
 
+#include "content/public/browser/web_contents.h"
 #include "extensions/shell/browser/shell_app_window.h"
+#include "ui/views/controls/webview/webview.h"
 
 namespace athena {
 
@@ -16,8 +18,18 @@ ShellAppActivity::ShellAppActivity(extensions::ShellAppWindow* app_window,
 ShellAppActivity::~ShellAppActivity() {
 }
 
-content::WebContents* ShellAppActivity::GetWebContents() {
-  return shell_app_window_->GetAssociatedWebContents();
+views::Widget* ShellAppActivity::CreateWidget() {
+  return NULL;  // Use default widget.
+}
+
+views::WebView* ShellAppActivity::GetWebView() {
+  content::WebContents* web_contents =
+      shell_app_window_->GetAssociatedWebContents();
+  views::WebView* web_view =
+      new views::WebView(web_contents->GetBrowserContext());
+  web_view->SetWebContents(web_contents);
+  Observe(web_contents);
+  return web_view;
 }
 
 }  // namespace athena