Inherit CSP when we inherit the security origin

This prevents attacks that use main window navigation to get out of the
existing csp constraints such as the related bug

Bug: 747847
Change-Id: I1e57b50da17f65d38088205b0a3c7c49ef2ae4d8
Reviewed-on: https://chromium-review.googlesource.com/592027
Reviewed-by: Mike West <mkwst@chromium.org>
Commit-Queue: Andy Paicu <andypaicu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492333}
void WebLocalFrameImpl::DispatchMessageEventWithOriginCheck(
    const WebSecurityOrigin& intended_target_origin,
    const WebDOMEvent& event) {
  DCHECK(!event.IsNull());
  GetFrame()->DomWindow()->DispatchMessageEventWithOriginCheck(
      intended_target_origin.Get(), event,
      SourceLocation::Create(String(), 0, 0, nullptr));
}

void WebLocalFrameImpl::DispatchMessageEventWithOriginCheck(
    const WebSecurityOrigin& intended_target_origin,
    const WebDOMEvent& event) {
  DCHECK(!event.IsNull());
  GetFrame()->DomWindow()->DispatchMessageEventWithOriginCheck(
      intended_target_origin.Get(), event,
      SourceLocation::Create(String(), 0, 0, nullptr));
}
