Don't focus the location bar for NTP navigations in non-selected tabs.

BUG=677716
TEST=See bug for repro steps.

Review-Url: https://codereview.chromium.org/2624373002
Cr-Commit-Position: refs/heads/master@{#443338}
gfx::Image Browser::GetCurrentPageIcon() const {
  WebContents* web_contents = tab_strip_model_->GetActiveWebContents();
  favicon::FaviconDriver* favicon_driver =
      web_contents
          ? favicon::ContentFaviconDriver::FromWebContents(web_contents)
          : nullptr;
  return favicon_driver ? favicon_driver->GetFavicon() : gfx::Image();
}

gfx::Image Browser::GetCurrentPageIcon() const {
  WebContents* web_contents = tab_strip_model_->GetActiveWebContents();
  favicon::FaviconDriver* favicon_driver =
      web_contents
          ? favicon::ContentFaviconDriver::FromWebContents(web_contents)
          : nullptr;
  return favicon_driver ? favicon_driver->GetFavicon() : gfx::Image();
}
