Credential Manager: Align 'FederatedCredential' with the spec.

public/platform/WebFederatedCredential.h

Index: public/platform/WebFederatedCredential.h
diff --git a/public/platform/WebFederatedCredential.h b/public/platform/WebFederatedCredential.h
index 3e38d78810af1b9422f92c2270ccdc096d04a16e..fb605ae6f9615b453f3cd5024409a2bb08ae4fd2 100644
--- a/public/platform/WebFederatedCredential.h
+++ b/public/platform/WebFederatedCredential.h
@@ -16,12 +16,11 @@ class WebFederatedCredential : public WebCredential {
 public:
     BLINK_PLATFORM_EXPORT WebFederatedCredential(const WebString& id, const WebURL& federation, const WebString& name, const WebURL& avatarURL);
 
-    // FIXME: Throw this away once it's unused on the chromium side.
-    BLINK_PLATFORM_EXPORT WebFederatedCredential(const WebString& id, const WebString& name, const WebURL& avatarURL, const WebURL& federation);
-
     BLINK_PLATFORM_EXPORT void assign(const WebFederatedCredential&);
+    BLINK_PLATFORM_EXPORT WebURL provider() const;
 
-    BLINK_PLATFORM_EXPORT WebURL federation() const;
+    // FIXME: Throw this away once it's unused on the Chromium side: https://crbug.com/494880
+    BLINK_PLATFORM_EXPORT WebURL federation() const { return provider(); }
 
 #if INSIDE_BLINK
     BLINK_PLATFORM_EXPORT WebFederatedCredential(PlatformCredential*);