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

content/public/browser/web_contents_observer.h

Index: content/public/browser/web_contents_observer.h
diff --git a/content/public/browser/web_contents_observer.h b/content/public/browser/web_contents_observer.h
index bacb7cc768fa39d708ffbce45a1ed1edba3eb68e..fe2dc9d1fc8dcc6e355999b6ff47937def0636fd 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -10,6 +10,7 @@
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/common/frame_navigate_params.h"
+#include "content/public/common/security_style.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "third_party/skia/include/core/SkColor.h"
@@ -176,6 +177,9 @@ class CONTENT_EXPORT WebContentsObserver : public IPC::Listener,
       const LoadCommittedDetails& details,
       const FrameNavigateParams& params) {}
 
+  // This method is invoked when the SecurityStyle of the WebContents changes.
+  virtual void SecurityStyleChanged(content::SecurityStyle security_style) {}
+
   // This method is invoked once the window.document object of the main frame
   // was created.
   virtual void DocumentAvailableInMainFrame() {}