Credential Manager: Add platform-exposed Credential objects.

Source/modules/credentialmanager/LocalCredential.cpp

Index: Source/modules/credentialmanager/LocalCredential.cpp
diff --git a/Source/modules/credentialmanager/LocalCredential.cpp b/Source/modules/credentialmanager/LocalCredential.cpp
index b04538fda813ce760491558a3cecddc88396aec6..9bfb6536ef25a5f13af990c96b258c65a8b9d1c3 100644
--- a/Source/modules/credentialmanager/LocalCredential.cpp
+++ b/Source/modules/credentialmanager/LocalCredential.cpp
@@ -4,6 +4,7 @@
 
 #include "config.h"
 #include "modules/credentialmanager/LocalCredential.h"
+#include "platform/credentialmanager/PlatformLocalCredential.h"
 
 namespace blink {
 
@@ -13,11 +14,15 @@ LocalCredential* LocalCredential::create(const String& id, const String& name, c
 }
 
 LocalCredential::LocalCredential(const String& id, const String& name, const String& avatarURL, const String& password)
-    : Credential(id, name, avatarURL)
-    , m_password(password)
+    : Credential(PlatformLocalCredential::create(id, name, avatarURL, password))
 {
 }
 
+const String& LocalCredential::password() const
+{
+    return static_cast<PlatformLocalCredential*>(m_private.get())->password();
+}
+
 LocalCredential::~LocalCredential()
 {
 }