[mojo] Add pickling support for native-only structs

This uses IPC::ParamTraits definitions as serializers for
native-only structs declared in mojom.

Part of a series of changes to support custom mojom serialization:

  1. https://codereview.chromium.org/1515423002
  2. https://codereview.chromium.org/1517043004
  3. https://codereview.chromium.org/1524693002
  4. https://codereview.chromium.org/1520153002
  5. https://codereview.chromium.org/1524613002
  6. This CL
  7. https://codereview.chromium.org/1524703002

BUG=569669
TBR=jam@chromium.org for DEPS +ipc/ipc_param_traits.h

Review URL: https://codereview.chromium.org/1526533002

Cr-Commit-Position: refs/heads/master@{#365847}


CrOS-Libchrome-Original-Commit: 2312b0ae91169d466ed79311698cf2f2eedf7c73
15 files changed
tree: f3c885514939b0f46ff8c9da895353576763e016
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/