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

content/public/browser/web_contents_delegate.cc

Index: content/public/browser/web_contents_delegate.cc
diff --git a/content/public/browser/web_contents_delegate.cc b/content/public/browser/web_contents_delegate.cc
index 8a384730d04e59f5cab5b457d4241574ac6e9028..1b6b4a0f880f3cacf8f56a2d9375adcae09ba758 100644
--- a/content/public/browser/web_contents_delegate.cc
+++ b/content/public/browser/web_contents_delegate.cc
@@ -278,4 +278,12 @@ void WebContentsDelegate::RequestAppBannerFromDevTools(
     content::WebContents* web_contents) {
 }
 
+bool WebContentsDelegate::ShouldAllowRunningInsecureContent(
+    WebContents* web_contents,
+    bool allowed_per_prefs,
+    const url::Origin& origin,
+    const GURL& resource_url) {
+  return allowed_per_prefs;
+}
+
 }  // namespace content