Credential Manager: Reject credential request if an outstanding request is pending.

components/password_manager/content/renderer/credential_manager_client.cc

Index: components/password_manager/content/renderer/credential_manager_client.cc
diff --git a/components/password_manager/content/renderer/credential_manager_client.cc b/components/password_manager/content/renderer/credential_manager_client.cc
index c753023d2ef10b43e6fcdbab4294b0460a2c21f1..aa128c51ed66bb9cbaa94518780974e205718519 100644
--- a/components/password_manager/content/renderer/credential_manager_client.cc
+++ b/components/password_manager/content/renderer/credential_manager_client.cc
@@ -56,6 +56,8 @@ bool CredentialManagerClient::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(CredentialManagerMsg_AcknowledgeSignedOut,
                         OnAcknowledgeSignedOut)
     IPC_MESSAGE_HANDLER(CredentialManagerMsg_SendCredential, OnSendCredential)
+    IPC_MESSAGE_HANDLER(CredentialManagerMsg_RejectCredentialRequest,
+                        OnRejectCredentialRequest)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -83,6 +85,15 @@ void CredentialManagerClient::OnSendCredential(int request_id,
   request_callbacks_.Remove(request_id);
 }
 
+void CredentialManagerClient::OnRejectCredentialRequest(int request_id) {
+  RequestCallbacks* callbacks = request_callbacks_.Lookup(request_id);
+  DCHECK(callbacks);
+  // We don't expose an internal failure to the page directly; model it as
+  // though no credentials were available.
+  callbacks->onSuccess(nullptr);
+  request_callbacks_.Remove(request_id);
+}
+
 // -----------------------------------------------------------------------------
 // Dispatch messages from the renderer to the browser.