Start rendering timer after first navigation

Currently the new content rendering timer in the browser process,
which clears an old page's contents 4 seconds after a navigation if the
new page doesn't draw in that time, is not set on the first navigation
for a top-level frame.

This is problematic because content can exist before the first
navigation, for instance if it was created by a javascript: URL.

This CL removes the code that skips the timer activation on the first
navigation.

Bug: 844881
Change-Id: I19b3ad1ff62c69ded3a5f7b1c0afde191aaf4584
Reviewed-on: https://chromium-review.googlesource.com/1188589
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Commit-Queue: Ken Buchanan <kenrb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586913}
RenderWidgetHost::GetRenderWidgetHosts() {
  std::unique_ptr<RenderWidgetHostIteratorImpl> hosts(
      new RenderWidgetHostIteratorImpl());
  for (auto& it : g_routing_id_widget_map.Get()) {
    RenderWidgetHost* widget = it.second;

    RenderViewHost* rvh = RenderViewHost::From(widget);
    if (!rvh) {
      hosts->Add(widget);
      continue;
    }

    if (static_cast<RenderViewHostImpl*>(rvh)->is_active())
      hosts->Add(widget);
  }

  return std::move(hosts);
}

RenderWidgetHost::GetRenderWidgetHosts() {
  std::unique_ptr<RenderWidgetHostIteratorImpl> hosts(
      new RenderWidgetHostIteratorImpl());
  for (auto& it : g_routing_id_widget_map.Get()) {
    RenderWidgetHost* widget = it.second;

    RenderViewHost* rvh = RenderViewHost::From(widget);
    if (!rvh) {
      hosts->Add(widget);
      continue;
    }

    if (static_cast<RenderViewHostImpl*>(rvh)->is_active())
      hosts->Add(widget);
  }

  return std::move(hosts);
}
