[sync] WebContentsObserver based sessions notifications

ios/chrome/browser/sync/ios_chrome_sync_client.mm

 // 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 "ios/chrome/browser/sync/ios_chrome_sync_client.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 62 matching lines @@
 namespace {
 
 // iOS implementation of SyncSessionsClient. Needs to be in a separate class
 // due to possible multiple inheritance issues, wherein IOSChromeSyncClient
 // might inherit from other interfaces with same methods.
 class SyncSessionsClientImpl : public sync_sessions::SyncSessionsClient {
  public:
   explicit SyncSessionsClientImpl(ios::ChromeBrowserState* browser_state)
       : browser_state_(browser_state),
         window_delegates_getter_(
-            base::MakeUnique<TabModelSyncedWindowDelegatesGetter>()) {}
+            base::MakeUnique<TabModelSyncedWindowDelegatesGetter>()),
+        local_session_event_router_(
+            base::MakeUnique<IOSChromeLocalSessionEventRouter>(
+                browser_state_,
+                this,
+                ios::sync_start_util::GetFlareForSyncableService(
+                    browser_state_->GetStatePath()))) {}
 
   ~SyncSessionsClientImpl() override {}
 
   // SyncSessionsClient implementation.
   bookmarks::BookmarkModel* GetBookmarkModel() override {
     DCHECK_CURRENTLY_ON(web::WebThread::UI);
     return ios::BookmarkModelFactory::GetForBrowserState(browser_state_);
   }
 
   favicon::FaviconService* GetFaviconService() override {
@@ skipping 16 matching lines @@
     }
     return url.is_valid() && !url.SchemeIs(kChromeUIScheme) &&
            !url.SchemeIsFile();
   }
 
   sync_sessions::SyncedWindowDelegatesGetter* GetSyncedWindowDelegatesGetter()
       override {
     return window_delegates_getter_.get();
   }
 
-  std::unique_ptr<sync_sessions::LocalSessionEventRouter>
-  GetLocalSessionEventRouter() override {
-    syncer::SyncableService::StartSyncFlare flare(
-        ios::sync_start_util::GetFlareForSyncableService(
-            browser_state_->GetStatePath()));
-    return base::MakeUnique<IOSChromeLocalSessionEventRouter>(browser_state_,
-                                                              this, flare);
+  sync_sessions::LocalSessionEventRouter* GetLocalSessionEventRouter()
+      override {
+    return local_session_event_router_.get();
   }
 
  private:
   ios::ChromeBrowserState* const browser_state_;
   const std::unique_ptr<sync_sessions::SyncedWindowDelegatesGetter>
       window_delegates_getter_;
+  const std::unique_ptr<IOSChromeLocalSessionEventRouter>
+      local_session_event_router_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncSessionsClientImpl);
 };
 
 }  // namespace
 
 IOSChromeSyncClient::IOSChromeSyncClient(ios::ChromeBrowserState* browser_state)
     : browser_state_(browser_state),
       sync_sessions_client_(
           base::MakeUnique<SyncSessionsClientImpl>(browser_state)),
@@ skipping 282 matching lines @@
         IOSChromeProfileSyncServiceFactory::GetForBrowserState(browser_state);
     if (profile_sync_service != nullptr) {
       const syncer::DeviceInfoTracker* tracker =
           profile_sync_service->GetDeviceInfoTracker();
       if (tracker != nullptr) {
         trackers->push_back(tracker);
       }
     }
   }
 }