Do not submit: high level overview patch.

chrome/browser/ui/android/tab_model/tab_model.cc

Index: chrome/browser/ui/android/tab_model/tab_model.cc
diff --git a/chrome/browser/ui/android/tab_model/tab_model.cc b/chrome/browser/ui/android/tab_model/tab_model.cc
index 9ecf3722826323e598d2d3b35a94519b198c3d51..ba3591bc484bdf751d15420232674da7a440e8dc 100644
--- a/chrome/browser/ui/android/tab_model/tab_model.cc
+++ b/chrome/browser/ui/android/tab_model/tab_model.cc
@@ -8,12 +8,15 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search_engines/search_terms_data.h"
+#include "chrome/browser/sync/glue/synced_tab_delegate.h"
 #include "chrome/browser/sync/glue/synced_window_delegate_android.h"
 #include "chrome/browser/ui/toolbar/toolbar_model_impl.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_service.h"
 
 using content::NotificationService;
+using browser_sync::SyncedTabDelegate;
+using browser_sync::SyncedWindowDelegate;
 
 TabModel::TabModel(Profile* profile)
   : profile_(profile),
@@ -36,6 +39,9 @@ TabModel::TabModel(Profile* profile)
                    content::Source<Profile>(profile_));
     registrar_.Add(this, chrome::NOTIFICATION_PROFILE_CREATED,
                    content::NotificationService::AllSources());
+    registrar_.Add(this,
+                   chrome::NOTIFICATION_SESSION_SYNC_ID_GENERATED,
+                   content::NotificationService::AllSources());
   } else {
     is_off_the_record_ = false;
   }
@@ -130,6 +136,24 @@ void TabModel::Observe(
           profile_ = profile;
       }
       break;
+    case chrome::NOTIFICATION_SESSION_SYNC_ID_GENERATED: {
+      content::Details<const SyncedTabDelegate> tab(details);
+      const SyncedWindowDelegate* sync_window_delegate =
+          SyncedWindowDelegate::FindSyncedWindowDelegateWithId(
+              tab->GetWindowId().id());
+      if (sync_window_delegate) {
+        const int tab_count = sync_window_delegate->GetTabCount();
+        for (int i = 0; i < tab_count; ++i) {
+          SyncedTabDelegate* sync_tab = sync_window_delegate->GetTabAt(i);
+          // This may seem redundant, but it ensure Sync id is set in java.
+          if (sync_tab && sync_tab->IsTabInMemory() &&
+              sync_tab->GetSyncSessionId() == tab->GetSyncSessionId()) {
+            sync_tab->SetSyncSessionId(tab->GetSyncSessionId());
+            break;
+          }
+        }
+      }
+    } break;
     default:
       NOTREACHED();
   }