Re-implement the screensaver to use WebView instead of ExtensionDialogHost.

ash/shell_delegate.h

Index: ash/shell_delegate.h
diff --git a/ash/shell_delegate.h b/ash/shell_delegate.h
index b08b0f8c52a91beef18a39ef476ef3617ead34cf..43c15936b0353c115368b5e3f9d663c52325402c 100644
--- a/ash/shell_delegate.h
+++ b/ash/shell_delegate.h
@@ -71,6 +71,9 @@ class ASH_EXPORT ShellDelegate {
   // Invoked when the user needs to set up mobile networking.
   virtual void OpenMobileSetup() = 0;
 
+  // Get the current browser context. This will get us the current profile.
+  virtual content::BrowserContext* GetCurrentBrowserContext() = 0;
+
   // Invoked when the user presses a shortcut to toggle spoken feedback
   // for accessibility.
   virtual void ToggleSpokenFeedback() = 0;