Creating PNG images from web content to be used by OverviewMode navigation

athena/content/app_activity.cc

Index: athena/content/app_activity.cc
diff --git a/athena/content/app_activity.cc b/athena/content/app_activity.cc
index da5f929847a701d836818d0eb14e652632e23148..f30336e17c4c02f1482f1352beeeee73aef36dad 100644
--- a/athena/content/app_activity.cc
+++ b/athena/content/app_activity.cc
@@ -29,9 +29,11 @@ AppActivity::AppActivity(extensions::AppWindow* app_window,
   Observe(app_window->web_contents());
 }
 
-scoped_ptr<ContentProxy> AppActivity::GetContentProxy(aura::Window* window) {
+scoped_ptr<ContentProxy> AppActivity::GetContentProxy() {
+  // Note: After this call, the content is still valid because the contents
+  // destruction will destroy this |AppActivity| object.
   if (content_proxy_.get())
-    content_proxy_->Reparent(window);
+    content_proxy_->OnPreContentDestroyed();
   return content_proxy_.Pass();
 }
 
@@ -147,10 +149,10 @@ views::View* AppActivity::GetContentsView() {
   return web_view_;
 }
 
-gfx::ImageSkia AppActivity::GetOverviewModeImage() {
+gfx::Image AppActivity::GetOverviewModeImage() {
   if (content_proxy_.get())
     return content_proxy_->GetContentImage();
-  return gfx::ImageSkia();
+  return gfx::Image();
 }
 
 void AppActivity::PrepareContentsForOverview() {