Update ChannelReader to use AttachmentBroker.

ipc/handle_attachment_win.cc

Index: ipc/handle_attachment_win.cc
diff --git a/ipc/handle_attachment_win.cc b/ipc/handle_attachment_win.cc
index dfce7c232e60087d8ee92a6523c8c50001bb9867..fefaff67f612c0bda5af1c3983b9159dc91fb619 100644
--- a/ipc/handle_attachment_win.cc
+++ b/ipc/handle_attachment_win.cc
@@ -14,10 +14,15 @@ HandleAttachmentWin::HandleAttachmentWin(const HANDLE& handle)
 }
 
 HandleAttachmentWin::HandleAttachmentWin(const WireFormat& wire_format)
-    : BrokerableAttachment(wire_format.attachment_id),
+    : BrokerableAttachment(wire_format.attachment_id, false),
       handle_(LongToHandle(wire_format.handle)) {
 }
 
+HandleAttachmentWin::HandleAttachmentWin(
+    const BrokerableAttachment::AttachmentId& id)
+    : BrokerableAttachment(id, true), handle_(INVALID_HANDLE_VALUE) {
+}
+
 HandleAttachmentWin::~HandleAttachmentWin() {
 }
 
@@ -26,6 +31,19 @@ HandleAttachmentWin::BrokerableType HandleAttachmentWin::GetBrokerableType()
   return WIN_HANDLE;
 }
 
+void HandleAttachmentWin::PopulateWithAttachment(
+    const BrokerableAttachment* attachment) {
+  DCHECK(NeedsBrokering());
+  DCHECK(!attachment->NeedsBrokering());
+  DCHECK(GetIdentifier() == attachment->GetIdentifier());
+  DCHECK_EQ(GetBrokerableType(), attachment->GetBrokerableType());
+
+  const HandleAttachmentWin* handle_attachment =
+      static_cast<const HandleAttachmentWin*>(attachment);
+  handle_ = handle_attachment->handle_;
+  SetNeedsBrokering(false);
+}
+
 HandleAttachmentWin::WireFormat HandleAttachmentWin::GetWireFormat(
     const base::ProcessId& destination) const {
   WireFormat format;