oauth2: new endpoints

Added *.Endpoint constants for facebook, linkedin, odnoklassniki, paypal
and vk.

Related to issue #41.

Change-Id: Ib447ff773a540aa9bc932a0e18d9bb9ef8703f87
Reviewed-on: https://go-review.googlesource.com/7370
Reviewed-by: Burcu Dogan <jbd@google.com>
diff --git a/facebook/facebook.go b/facebook/facebook.go
new file mode 100644
index 0000000..962e86b
--- /dev/null
+++ b/facebook/facebook.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The oauth2 Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package facebook provides constants for using OAuth2 to access Facebook.
+package facebook // import "golang.org/x/oauth2/facebook"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is Facebook's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://www.facebook.com/dialog/oauth",
+	TokenURL: "https://graph.facebook.com/oauth/access_token",
+}
diff --git a/linkedin/linkedin.go b/linkedin/linkedin.go
new file mode 100644
index 0000000..de91d5b
--- /dev/null
+++ b/linkedin/linkedin.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The oauth2 Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package linkedin provides constants for using OAuth2 to access LinkedIn.
+package linkedin // import "golang.org/x/oauth2/linkedin"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is LinkedIn's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://www.linkedin.com/uas/oauth2/authorization",
+	TokenURL: "https://www.linkedin.com/uas/oauth2/accessToken",
+}
diff --git a/odnoklassniki/odnoklassniki.go b/odnoklassniki/odnoklassniki.go
new file mode 100644
index 0000000..2f7a962
--- /dev/null
+++ b/odnoklassniki/odnoklassniki.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The oauth2 Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package odnoklassniki provides constants for using OAuth2 to access Odnoklassniki.
+package odnoklassniki // import "golang.org/x/oauth2/odnoklassniki"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is Odnoklassniki's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://www.odnoklassniki.ru/oauth/authorize",
+	TokenURL: "https://api.odnoklassniki.ru/oauth/token.do",
+}
diff --git a/paypal/paypal.go b/paypal/paypal.go
new file mode 100644
index 0000000..baeaa23
--- /dev/null
+++ b/paypal/paypal.go
@@ -0,0 +1,22 @@
+// Copyright 2015 The oauth2 Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package paypal provides constants for using OAuth2 to access PayPal.
+package paypal // import "golang.org/x/oauth2/paypal"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is PayPal's OAuth 2.0 endpoint in live (production) environment.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://www.paypal.com/webapps/auth/protocol/openidconnect/v1/authorize",
+	TokenURL: "https://api.paypal.com/v1/identity/openidconnect/tokenservice",
+}
+
+// SandboxEndpoint is PayPal's OAuth 2.0 endpoint in sandbox (testing) environment.
+var SandboxEndpoint = oauth2.Endpoint{
+	AuthURL:  "https://www.sandbox.paypal.com/webapps/auth/protocol/openidconnect/v1/authorize",
+	TokenURL: "https://api.sandbox.paypal.com/v1/identity/openidconnect/tokenservice",
+}
diff --git a/vk/vk.go b/vk/vk.go
new file mode 100644
index 0000000..5acdeb1
--- /dev/null
+++ b/vk/vk.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The oauth2 Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package vk provides constants for using OAuth2 to access VK.com.
+package vk // import "golang.org/x/oauth2/vk"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is VK's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://oauth.vk.com/authorize",
+	TokenURL: "https://oauth.vk.com/access_token",
+}