Fixed bug where PlzNavigate CSP in a iframe did not get the inherited CSP

When inheriting the CSP from a parent document to a local-scheme CSP,
it does not always get propagated to the PlzNavigate CSP. This means
that PlzNavigate CSP checks (like `frame-src`) would be ran against
a blank policy instead of the proper inherited policy.

Bug: 778658
Change-Id: I61bb0d432e1cea52f199e855624cb7b3078f56a9
Reviewed-on: https://chromium-review.googlesource.com/765969
Commit-Queue: Andy Paicu <andypaicu@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518245}
void Document::TraceWrappers(const ScriptWrappableVisitor* visitor) const {
  visitor->TraceWrappers(imports_controller_);
  visitor->TraceWrappers(parser_);
  visitor->TraceWrappers(implementation_);
  visitor->TraceWrappers(style_sheet_list_);
  visitor->TraceWrappers(style_engine_);
  visitor->TraceWrappers(script_runner_);
  visitor->TraceWrappers(scripted_animation_controller_);
  visitor->TraceWrappers(scripted_idle_task_controller_);
  ContainerNode::TraceWrappers(visitor);
  Supplementable<Document>::TraceWrappers(visitor);
}

void Document::TraceWrappers(const ScriptWrappableVisitor* visitor) const {
  visitor->TraceWrappers(imports_controller_);
  visitor->TraceWrappers(parser_);
  visitor->TraceWrappers(implementation_);
  visitor->TraceWrappers(style_sheet_list_);
  visitor->TraceWrappers(style_engine_);
  visitor->TraceWrappers(script_runner_);
  visitor->TraceWrappers(scripted_animation_controller_);
  visitor->TraceWrappers(scripted_idle_task_controller_);
  ContainerNode::TraceWrappers(visitor);
  Supplementable<Document>::TraceWrappers(visitor);
}
