Update to Chromium revision 304f01a1 (#358063)

- Improve ordering of CefLoadHandler callbacks. OnLoadingStateChange will
  be called before and after all calls to OnLoadStart and OnLoadEnd.
  OnLoadStart/OnLoadEnd calls will occur as matching pairs
  (see http://crbug.com/539952#c2).
- Remove the |requesting_url| argument to CefGeolocationHandler::
  OnCancelGeolocationPermission. Clients can use the |request_id| argument
  to track this information themselves.
- Fix a crash when loading the PDF extension in multiple browsers with a
  custom CefRequestContext (issue #1757).

libcef/browser/extensions/extensions_api_client.h

@@ -16,6 +16,9 @@ class CefExtensionsAPIClient : public ExtensionsAPIClient {
 
   // ExtensionsAPIClient implementation.
   AppViewGuestDelegate* CreateAppViewGuestDelegate() const override;
+  scoped_ptr<guest_view::GuestViewManagerDelegate>
+  CreateGuestViewManagerDelegate(
+      content::BrowserContext* context) const override;
   scoped_ptr<MimeHandlerViewGuestDelegate>
   CreateMimeHandlerViewGuestDelegate(
       MimeHandlerViewGuest* guest) const override;