PlzNavigate: Move navigation-level mixed content checks to the browser.

content/browser/frame_host/render_frame_host_delegate.cc

Index: content/browser/frame_host/render_frame_host_delegate.cc
diff --git a/content/browser/frame_host/render_frame_host_delegate.cc b/content/browser/frame_host/render_frame_host_delegate.cc
index cb8545c3e365ea90a6f8baa6ceb37f133e7dce05..e260c8e7c2c646a78da9f7e6b998e4bf8a9c831a 100644
--- a/content/browser/frame_host/render_frame_host_delegate.cc
+++ b/content/browser/frame_host/render_frame_host_delegate.cc
@@ -93,4 +93,12 @@ RenderFrameHostDelegate::CreateWebUIForRenderFrameHost(const GURL& url) {
   return nullptr;
 }
 
+bool RenderFrameHostDelegate::ShouldAllowRunningInsecureContent(
+    WebContents* web_contents,
+    bool allowed_per_prefs,
+    const url::Origin& origin,
+    const GURL& resource_url) {
+  return false;
+}
+
 }  // namespace content