Expand SecurityStyleChanged interfaces to include explanations

content/public/browser/security_style_explanation.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/public/browser/security_style_explanation.h"
+
+namespace content {
+
+SecurityStyleExplanation::SecurityStyleExplanation() {
+}
+
+SecurityStyleExplanation::SecurityStyleExplanation(
+    const std::string& summary,
+    const std::string& description)
+    : summary(summary), description(description) {
+}
+
+SecurityStyleExplanation::~SecurityStyleExplanation() {
+}
+
+}  // namespace content