Prevent leaking PDF data cross-origin

BUG=520422

Review URL: https://codereview.chromium.org/1311973002

Cr-Commit-Position: refs/heads/master@{#345267}
void OutOfProcessInstance::UserMetricsRecordAction(
    const std::string& action) {
  pp::PDF::UserMetricsRecordAction(this, pp::Var(action));
}

void OutOfProcessInstance::UserMetricsRecordAction(
    const std::string& action) {
  pp::PDF::UserMetricsRecordAction(this, pp::Var(action));
}
