IPC: Add MojoHandleAttachment

ipc/ipc_message_attachment_set.cc

Index: ipc/ipc_message_attachment_set.cc
diff --git a/ipc/ipc_message_attachment_set.cc b/ipc/ipc_message_attachment_set.cc
index dd881c5843f1090c210134ab3821c20e85da75bf..f64673db65852a7759fdec3fa927ab127d4c7522 100644
--- a/ipc/ipc_message_attachment_set.cc
+++ b/ipc/ipc_message_attachment_set.cc
@@ -45,6 +45,13 @@ unsigned MessageAttachmentSet::num_descriptors() const {
   });
 }
 
+unsigned MessageAttachmentSet::num_mojo_handles() const {
+  return std::count_if(attachments_.begin(), attachments_.end(),
+                       [](scoped_refptr<MessageAttachment> i) {
+    return i->GetType() == MessageAttachment::TYPE_MOJO_HANDLE;
+  });
+}
+
 unsigned MessageAttachmentSet::size() const {
   return static_cast<unsigned>(attachments_.size());
 }
@@ -52,7 +59,7 @@ unsigned MessageAttachmentSet::size() const {
 bool MessageAttachmentSet::AddAttachment(
     scoped_refptr<MessageAttachment> attachment) {
 #if defined(OS_POSIX)
-  if (attachment->GetType() != MessageAttachment::TYPE_PLATFORM_FILE ||
+  if (attachment->GetType() == MessageAttachment::TYPE_PLATFORM_FILE &&
       num_descriptors() == kMaxDescriptorsPerMessage) {
     DLOG(WARNING) << "Cannot add file descriptor. MessageAttachmentSet full.";
     return false;