[sync] WebContentsObserver based sessions notifications

chrome/browser/ui/tab_helpers.cc

Index: chrome/browser/ui/tab_helpers.cc
diff --git a/chrome/browser/ui/tab_helpers.cc b/chrome/browser/ui/tab_helpers.cc
index 1a04c4d5f6d01086e8b0094f218de127354d6609..3bc626e3ce01e8aa261f7a04023e1027eeafb2ce 100644
--- a/chrome/browser/ui/tab_helpers.cc
+++ b/chrome/browser/ui/tab_helpers.cc
@@ -37,6 +37,8 @@
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "chrome/browser/ssl/security_state_tab_helper.h"
 #include "chrome/browser/subresource_filter/chrome_subresource_filter_client.h"
+#include "chrome/browser/sync/sessions/sync_sessions_router_tab_helper.h"
+#include "chrome/browser/sync/sessions/sync_sessions_web_contents_router_factory.h"
 #include "chrome/browser/tab_contents/navigation_metrics_recorder.h"
 #include "chrome/browser/tracing/navigation_tracing.h"
 #include "chrome/browser/translate/chrome_translate_client.h"
@@ -207,6 +209,10 @@ void TabHelpers::AttachTabHelpers(WebContents* web_contents) {
     MixedContentSettingsTabHelper::CreateForWebContents(web_contents);
   metrics::RendererUptimeWebContentsObserver::CreateForWebContents(
       web_contents);
+  sync_sessions::SyncSessionsRouterTabHelper::CreateForWebContents(
+      web_contents,
+      sync_sessions::SyncSessionsWebContentsRouterFactory::GetForProfile(
+          Profile::FromBrowserContext(web_contents->GetBrowserContext())));
 
   // --- Platform-specific tab helpers ---