The document summarizes a discussion between Apple, Google, and a developer about Google's use of Safari to handle login for Google+ authentication in iOS apps. Apple says this is only allowed for Facebook and that Google should implement web-view login instead. Google argues that using Safari for single sign-on has better usability. The document provides examples of "horrible fixes" a developer could use to handle Google login within the app instead of switching to Safari.

1. Kevin Donnelly
@donnellyk

2. GOOGLE+, APP REVIEW, AND
YOUA CAUTIONARY TALE

3. Google+ log-in opens a web page in mobile Safari for logging in, then
returns the user to the app. The user should be able log in without
opening Safari first.
10.6: Apple and our customers place a high value on simple, refined,
creative, well thought through interfaces. They take more work but are
worth it.

4. APPLE'S RESPONSE
Hello, Jumping to Safari and to an app is only approved for Facebook,
among social networks. If the removal of the Google+ login is the
solution, please update the screenshots to match the interface. If you
choose to keep it in, please implement web-view for login.

5. Issue 900 on google-plus-platform
First reported back on July 4th, 2014

6. GOOGLE'S RESPONSE
The Google Sign-In button does a fast app-switch on iOS because it is
the best way to achieve single sign-on, where the user only needs to
enter their password once per device. Google believes any usability
issue of the app-switch is greatly outweighed by the usability benefit of
only needing to enter your Google password once per device.

7. A (HORRIBLE) FIX
- (BOOL)openURL:(NSURL*)url {
if ([[url absoluteString] hasPrefix:
@"https://accounts.google.com/o/oauth2/auth"]) {
[[NSNotificationCenter defaultCenter]
postNotificationName:ApplicationOpenGoogleAuthNotification
object:url];
return NO;
}
return [super openURL:url];
}

8. SIDEBAR
Change
return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
To
return UIApplicationMain(argc, argv, NSStringFromClass([UIApplicationSubclass class]),
NSStringFromClass([AppDelegate class]));

9. MORE (HORRIBLE) FIXES
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
if ([[[request URL] absoluteString] hasPrefix:
@"com.bundle.id:/oauth2callback"]) {
[GPPURLHandler handleURL:url
sourceApplication:@"com.google.chrome.ios" annotation:nil];
[self.navigationController popViewControllerAnimated:YES];
return NO;
}
return YES;
}
More detailed Stackoverflow answer

10. "We do not support hand-rolled/embedded UIWebView for reasons of
security, though are well aware of the unsavory tradeoff currently in
place."