IPC: Get rid of FileDescriptor usage from FileDescriptorSet and Message

ipc/mojo/ipc_channel_mojo.cc

Index: ipc/mojo/ipc_channel_mojo.cc
diff --git a/ipc/mojo/ipc_channel_mojo.cc b/ipc/mojo/ipc_channel_mojo.cc
index 71c373e01cf07a63708871ae3077c121fc0f3e31..eb92d63f352dd094c55e76cd8eca8aaaccd06bc9 100644
--- a/ipc/mojo/ipc_channel_mojo.cc
+++ b/ipc/mojo/ipc_channel_mojo.cc
@@ -248,7 +248,8 @@ MojoResult ChannelMojo::WriteToFileDescriptorSet(
       return unwrap_result;
     }
 
-    bool ok = message->file_descriptor_set()->Add(platform_handle.release().fd);
+    bool ok = message->file_descriptor_set()->AddToBorrow(
+        platform_handle.release().fd);
     DCHECK(ok);
   }
 
@@ -264,8 +265,10 @@ MojoResult ChannelMojo::ReadFromFileDescriptorSet(
   // of FDs, so just to dup()-and-own them is the safest option.
   if (message.HasFileDescriptors()) {
     const FileDescriptorSet* fdset = message.file_descriptor_set();
-    for (size_t i = 0; i < fdset->size(); ++i) {
-      int fd_to_send = dup(fdset->GetDescriptorAt(i));
+    std::vector<base::PlatformFile> fds_to_send(fdset->size());
+    fdset->GetDescriptors(&fds_to_send[0]);
+    for (size_t i = 0; i < fds_to_send.size(); ++i) {
+      int fd_to_send = dup(fds_to_send[i]);
       if (-1 == fd_to_send) {
         DPLOG(WARNING) << "Failed to dup FD to transmit.";
         return MOJO_RESULT_UNKNOWN;