Make IPC::ParamTraits<>GetSize work with base::Value as a result of JSON parsing.

The JSON parser uses a JSONStringValue for string values, which looks almost
like a base::StringValue, but doesn't support GetAsString(base::StringValue**).

BUG=597124

Review URL: https://codereview.chromium.org/1866633002

Cr-Commit-Position: refs/heads/master@{#385989}


CrOS-Libchrome-Original-Commit: c7a7a767d643aef68eb2af82f961c11872abe59d
2 files changed
tree: 67430054757394f62ea0038ea808300b8c2e4fa8
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/