[sync] WebContentsObserver based sessions notifications

chrome/browser/sync/sessions/browser_list_router_helper.cc

+// Copyright 2017 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 "chrome/browser/sync/sessions/browser_list_router_helper.h"
+
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/sync/tab_contents_synced_tab_delegate.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+
+namespace sync_sessions {
+
+BrowserListRouterHelper::BrowserListRouterHelper(
+    SyncSessionsWebContentsRouter* router)
+    : router_(router) {
+  BrowserList* browser_list = BrowserList::GetInstance();
+  for (Browser* browser : *browser_list)
+    browser->tab_strip_model()->AddObserver(this);
+  browser_list->AddObserver(this);
+}
+
+BrowserListRouterHelper::~BrowserListRouterHelper() {
+  BrowserList* browser_list = BrowserList::GetInstance();
+  for (Browser* browser : *browser_list)
+    browser->tab_strip_model()->RemoveObserver(this);
+  BrowserList::GetInstance()->RemoveObserver(this);
+}
+
+void BrowserListRouterHelper::OnBrowserAdded(Browser* browser) {
+  browser->tab_strip_model()->AddObserver(this);
+}
+
+void BrowserListRouterHelper::OnBrowserRemoved(Browser* browser) {
+  browser->tab_strip_model()->RemoveObserver(this);
+}
+
+void BrowserListRouterHelper::TabInsertedAt(TabStripModel* model,
+                                            content::WebContents* web_contents,
+                                            int index,
+                                            bool foreground) {
+  router_->NotifyTabModified(web_contents);
+}
+
+}  // namespace sync_sessions