Introduce browser-side plumbing for sending the lock icon status to DevTools.

content/public/common/security_style.h

Index: content/public/common/security_style.h
diff --git a/content/public/common/security_style.h b/content/public/common/security_style.h
index 94cd0ed99d9eaee70cb84135ae0f95f6f24f1f3f..a0086d5a64ceeb4a987187574d2d66e2bfb8c629 100644
--- a/content/public/common/security_style.h
+++ b/content/public/common/security_style.h
@@ -28,6 +28,11 @@ enum SecurityStyle {
   // this object in an authenticated manner but were unable to do so.
   SECURITY_STYLE_AUTHENTICATION_BROKEN,
 
+  // SECURITY_STYLE_WARNING means that the object was retrieved in an
+  // authenticated manner, but there were security issues with the retrieval or
+  // the object interacted with less secure objects.
+  SECURITY_STYLE_WARNING,
+
   // SECURITY_STYLE_AUTHENTICATED indicates that we successfully retrieved this
   // object over an authenticated protocol, such as HTTPS.
   SECURITY_STYLE_AUTHENTICATED,