Generalize WebContentsObserver::SecurityStyleChanged

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 77502effa5001bf50b23e2a7edbbab1ed302d4d7..1fc91881d51da3dedf48093e503d166bba3d17c5 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -41,7 +41,6 @@ struct LoadCommittedDetails;
 struct Referrer;
 struct ResourceRedirectDetails;
 struct ResourceRequestDetails;
-struct SecurityStyleExplanations;
 
 // An observer API implemented by classes which are interested in various page
 // load events from WebContents.  They also get a chance to filter IPC messages.
@@ -297,13 +296,8 @@ class CONTENT_EXPORT WebContentsObserver : public IPC::Listener,
                            const base::string16& error_description,
                            bool was_ignored_by_handler) {}
 
-  // This method is invoked when the SecurityStyle of the WebContents changes.
-  // |security_style| is the new SecurityStyle. |security_style_explanations|
-  // contains human-readable strings explaining why the SecurityStyle of the
-  // page has been downgraded.
-  virtual void SecurityStyleChanged(
-      blink::WebSecurityStyle security_style,
-      const SecurityStyleExplanations& security_style_explanations) {}
+  // This method is invoked when the visible security state of the page changes.
+  virtual void DidChangeVisibleSecurityState() {}

[clamy, 2016/12/09 14:25:44]

This method does not seem to be used outside of content/ except in unit tests.
Is that normal?

[cjgrant, 2016/12/09 16:08:29]

I've rebased this on top of CL 2556963006, which landed yesterday.  It shows
what VrShell is trying to achieve (ie. using a WebContentsObserver, but fishing
for security information that content isn't aware of).  I'm still trying to
grasp the detailed boundaries of the content API, and the previous comments on
this review help.  If you think I should be doing this differently, let me know!

[estark, 2016/12/09 16:12:44]

That's normal for WebContentsObserver methods, see e.g. OnWebContentsFocused,
AccessibilityEventReceived, BeforeUnloadFired, UserAgentOverrideSet, etc.

 
   // This method is invoked when content was loaded from an in-memory cache.
   virtual void DidLoadResourceFromMemoryCache(