Update mojo sdk to rev 912f52f69dadbe1e3cf9576f26731863770bcfc3

third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h

Index: third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h
diff --git a/third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h b/third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h
index 34efcad5275a7d121166ba2034abcbba76ce26ca..3073632e5098b2abbf17d46bfbb22466d9cbd110 100644
--- a/third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h
+++ b/third_party/mojo/src/mojo/edk/embedder/platform_channel_utils_posix.h
@@ -21,9 +21,9 @@ namespace embedder {
 
 // The maximum number of handles that can be sent "at once" using
 // |PlatformChannelSendmsgWithHandles()|.
-// TODO(vtl): This number is taken from ipc/file_descriptor_set_posix.h:
-// |FileDescriptorSet::kMaxDescriptorsPerMessage|. Where does it come from?
-const size_t kPlatformChannelMaxNumHandles = 7;
+// TODO(vtl): This number is taken from ipc/ipc_message_attachment_set.h:
+// |IPC::MessageAttachmentSet::kMaxDescriptorsPerMessage|.
+const size_t kPlatformChannelMaxNumHandles = 128;
 
 // Use these to write to a socket created using |PlatformChannelPair| (or
 // equivalent). These are like |write()| and |writev()|, but handle |EINTR| and