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 7410d178fa401ceba7e9c696637ae866a738cf68..e45d91db1545d34eb33a05cd0f73e713dade1c87 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_settings,
+    const url::Origin& origin,
+    const GURL& resource_url) {
+  return false;
+}
+
 }  // namespace content