Make attachment broker a subclass of IPC::Listener.

ipc/attachment_broker_win.h

Index: ipc/attachment_broker_win.h
diff --git a/ipc/attachment_broker_win.h b/ipc/attachment_broker_win.h
index 1cf4348b68120406934172713abd6b8188a1b752..5df2c9a2395b9fcba21d7d53307db751112d7148 100644
--- a/ipc/attachment_broker_win.h
+++ b/ipc/attachment_broker_win.h
@@ -5,7 +5,12 @@
 #ifndef IPC_ATTACHMENT_BROKER_WIN_H_
 #define IPC_ATTACHMENT_BROKER_WIN_H_
 
+#include <vector>
+
+#include "base/gtest_prod_util.h"
+#include "base/memory/ref_counted.h"
 #include "ipc/attachment_broker.h"
+#include "ipc/handle_attachment_win.h"
 #include "ipc/ipc_export.h"
 
 namespace IPC {
@@ -29,11 +34,28 @@ class IPC_EXPORT AttachmentBrokerWin : public IPC::AttachmentBroker {
   bool GetAttachmentWithId(BrokerableAttachment::AttachmentId id,
                            BrokerableAttachment* attachment) override;
 
+  // IPC::Listener overrides.
+  bool OnMessageReceived(const Message& message) override;
+
   // |sender_| is used to send Messages to the broker. |sender_| must live at
   // least as long as this instance.
   void set_sender(IPC::Sender* sender) { sender_ = sender; }
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(AttachmentBrokerWinTest, ReceiveValidMessage);
+  FRIEND_TEST_ALL_PREFIXES(AttachmentBrokerWinTest, ReceiveInvalidMessage);
+
+  // IPC message handlers.
+  void OnWinHandleHasBeenDuplicated(
+      const IPC::internal::HandleAttachmentWin::WireFormat& wire_format);
+
+  // A vector of BrokerableAttachments that have been received, but not yet
+  // consumed.
+  // A std::vector is used instead of a std::map because this container is
+  // expected to have few elements, for which a std::vector is expected to have
+  // better performance.
+  std::vector<scoped_refptr<BrokerableAttachment>> attachments_;
+
   // |sender_| is used to send Messages to the broker. |sender_| must live at
   // least as long as this instance.
   IPC::Sender* sender_;