Generalize WebContentsObserver::SecurityStyleChanged.

This will put the onus on individual observers to extract the security
information they require, after a change has occurred.  The intent is to
allow chrome/browser-residing observers to monitor security level
changes, independent of style.

BUG=641508

Review-Url: https://codereview.chromium.org/2562503002
Cr-Commit-Position: refs/heads/master@{#437659}
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index fa0b7da..4a1d2fb 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1471,14 +1471,8 @@
 void WebContentsImpl::DidChangeVisibleSecurityState() {
   if (delegate_) {
     delegate_->VisibleSecurityStateChanged(this);
-
-    SecurityStyleExplanations security_style_explanations;
-    blink::WebSecurityStyle security_style =
-        delegate_->GetSecurityStyle(this, &security_style_explanations);
-    for (auto& observer : observers_) {
-      observer.SecurityStyleChanged(security_style,
-                                    security_style_explanations);
-    }
+    for (auto& observer : observers_)
+      observer.DidChangeVisibleSecurityState();
   }
 }