Remove IPC::BrokerableAttachment.

ipc/ipc_message_attachment.h

Index: ipc/ipc_message_attachment.h
diff --git a/ipc/ipc_message_attachment.h b/ipc/ipc_message_attachment.h
index 7f7137d87b20f7483fdcfbfc75406ed1beb1c5fc..9ff1de8c32f53b6b8ce709ab3891ae2e2398b69e 100644
--- a/ipc/ipc_message_attachment.h
+++ b/ipc/ipc_message_attachment.h
@@ -10,6 +10,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/pickle.h"
 #include "build/build_config.h"
+#include "ipc/ipc.mojom.h"
 #include "ipc/ipc_export.h"
 
 namespace IPC {
@@ -18,18 +19,10 @@ namespace IPC {
 // or a mojo |MessagePipe|. |GetType()| returns the type of the subclass.
 class IPC_EXPORT MessageAttachment : public base::Pickle::Attachment {
  public:
-  enum Type {
-    TYPE_PLATFORM_FILE,          // The instance is |PlatformFileAttachment|.
-    TYPE_MOJO_HANDLE,            // The instance is |MojoHandleAttachment|.
-    TYPE_BROKERABLE_ATTACHMENT,  // The instance is |BrokerableAttachment|.
-  };
+  using Type = mojom::SerializedHandle::Type;
 
   virtual Type GetType() const = 0;
 
-#if defined(OS_POSIX)
-  virtual base::PlatformFile TakePlatformFile() = 0;
-#endif  // OS_POSIX
-
  protected:
   friend class base::RefCountedThreadSafe<MessageAttachment>;
   MessageAttachment();