OAuth -- generalize / refactor providers and diagnostics page

Summary: split out from D1595

Test Plan: oauth/facebook/diagnose still looks good!

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D1632

src/applications/auth/oauth/provider/github/PhabricatorOAuthProviderGitHub.php

@@ -40,18 +40,22 @@ class PhabricatorOAuthProviderGitHub extends PhabricatorOAuthProvider {
     return PhabricatorEnv::getEnvConfig('github.registration-enabled');
   }
 
-  public function getRedirectURI() {
-    return PhabricatorEnv::getURI('/oauth/github/login/');
-  }
-
   public function getClientID() {
     return PhabricatorEnv::getEnvConfig('github.application-id');
   }
 
+  public function renderGetClientIDHelp() {
+    return null;
+  }
+
   public function getClientSecret() {
     return PhabricatorEnv::getEnvConfig('github.application-secret');
   }
 
+  public function renderGetClientSecretHelp() {
+    return null;
+  }
+
   public function getAuthURI() {
     return 'https://github.com/login/oauth/authorize';
   }
@@ -60,6 +64,12 @@ class PhabricatorOAuthProviderGitHub extends PhabricatorOAuthProvider {
     return 'https://github.com/login/oauth/access_token';
   }
 
+  public function getTestURIs() {
+    return array(
+      'http://github.com',
+    );
+  }
+
   public function getUserInfoURI() {
     return 'https://github.com/api/v2/json/user/show';
   }