[sync] WebContentsObserver based sessions notifications

chrome/browser/sync/sessions/sync_sessions_web_contents_router.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/sync_sessions_web_contents_router.h"
+
+#include "chrome/browser/history/history_service_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/sync/tab_contents_synced_tab_delegate.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "components/history/core/browser/history_service.h"
+#include "components/sync_sessions/synced_tab_delegate.h"
+
+namespace sync_sessions {
+
+SyncSessionsWebContentsRouter::SyncSessionsWebContentsRouter(Profile* profile) {
+  history::HistoryService* history_service =
+      HistoryServiceFactory::GetForProfile(profile,
+                                           ServiceAccessType::EXPLICIT_ACCESS);
+  if (history_service) {
+    favicon_changed_subscription_ = history_service->AddFaviconsChangedCallback(
+        base::Bind(&SyncSessionsWebContentsRouter::OnFaviconsChanged,
+                   base::Unretained(this)));
+  }
+}
+
+SyncSessionsWebContentsRouter::~SyncSessionsWebContentsRouter() {}
+
+void SyncSessionsWebContentsRouter::NotifyTabModified(
+    content::WebContents* web_contents) {
+  if (handler_ && web_contents) {
+    SyncedTabDelegate* delegate =
+        TabContentsSyncedTabDelegate::FromWebContents(web_contents);
+    if (delegate)
+      handler_->OnLocalTabModified(delegate);
+  }
+
+  if (!flare_.is_null()) {
+    flare_.Run(syncer::SESSIONS);
+    flare_.Reset();
+  }
+}
+
+void SyncSessionsWebContentsRouter::InjectStartSyncFlare(
+    syncer::SyncableService::StartSyncFlare flare) {
+  flare_ = flare;
+}
+
+void SyncSessionsWebContentsRouter::StartRoutingTo(
+    LocalSessionEventHandler* handler) {
+  handler_ = handler;
+}
+
+void SyncSessionsWebContentsRouter::Stop() {
+  handler_ = nullptr;
+}
+
+void SyncSessionsWebContentsRouter::OnFaviconsChanged(
+    const std::set<GURL>& page_urls,
+    const GURL& icon_url) {
+  if (handler_)
+    handler_->OnFaviconsChanged(page_urls, icon_url);
+}
+
+void SyncSessionsWebContentsRouter::Shutdown() {
+  favicon_changed_subscription_.reset();
+}
+
+}  // namespace sync_sessions