Credential Manager: Migrate to WebView client-based approach.

public/platform/WebCredentialManagerClient.h

Index: public/platform/WebCredentialManagerClient.h
diff --git a/public/platform/WebCredentialManager.h b/public/platform/WebCredentialManagerClient.h
similarity index 73%
rename from public/platform/WebCredentialManager.h
rename to public/platform/WebCredentialManagerClient.h
index 9bd239acf34f2ab8c538681b1c1c342d0102430c..038a1a57808eb2e23bc97ad380ff814e23ceb4bd 100644
--- a/public/platform/WebCredentialManager.h
+++ b/public/platform/WebCredentialManagerClient.h
@@ -2,27 +2,28 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef WebCredentialManager_h
-#define WebCredentialManager_h
+#ifndef WebCredentialManagerClient_h
+#define WebCredentialManagerClient_h
 
 #include "public/platform/WebCallbacks.h"
 #include "public/platform/WebCredentialManagerError.h"
-#include "public/platform/WebString.h"
 #include "public/platform/WebVector.h"
 
 namespace blink {
 
-// WebCredentialManager provides an interface for asking Blink's embedder to
-// respond to `navigator.credentials.*` calls.
-class WebCredentialManager {
+class WebCredential;
+class WebURL;
+
+// WebCredentialManagerClient is an interface which allows an embedder to
+// implement 'navigator.credential.*' calls which are defined in the
+// 'credentialmanager' module.
+class WebCredentialManagerClient {
 public:
     typedef WebCallbacks<WebCredential, WebCredentialManagerError> RequestCallbacks;
     typedef WebCallbacks<void, WebCredentialManagerError> NotificationCallbacks;
 
-    WebCredentialManager() { }
-    virtual ~WebCredentialManager() { }
-
-    // Ownership of the callback is transferred to the callee for each of the following methods.
+    // Ownership of the callback is transferred to the callee for each of
+    // the following methods.
     virtual void dispatchFailedSignIn(const WebCredential&, NotificationCallbacks*) { }
     virtual void dispatchSignedIn(const WebCredential&, NotificationCallbacks*) { }
     virtual void dispatchSignedOut(NotificationCallbacks*) { }