Update template message for destruction of mojo callback.

The template message implies that the callback must be run before destroyed.
This has caused confusion for me, and others, e.g. see
https://bugs.chromium.org/p/chromium/issues/detail?id=788658#c4. Instead, the
error should state that either: the callback should be run before it is
destroyed, or else it should be destroyed after the pipe is closed.

Bug: 
Change-Id: Iad5a75332fe2284538ef1d428a6e4572fdc2b551
Reviewed-on: https://chromium-review.googlesource.com/794571
Reviewed-by: Ken Rockot <rockot@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519939}

CrOS-Libchrome-Original-Commit: 364cc9e9972246f33e4ed28b61d5295102c45001
1 file changed
tree: 01f42b3ce093ee8dc897a0f2114c3e5eb812255c
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/