[sync] WebContentsObserver based sessions notifications

ios/chrome/browser/sync/ios_chrome_synced_tab_delegate.mm

Index: ios/chrome/browser/sync/ios_chrome_synced_tab_delegate.mm
diff --git a/ios/chrome/browser/sync/ios_chrome_synced_tab_delegate.mm b/ios/chrome/browser/sync/ios_chrome_synced_tab_delegate.mm
index 67a293675af802864e754c0686c30e29c110def3..cdca78c032dc2c1f4d37af3c596dff8ee5ed68e7 100644
--- a/ios/chrome/browser/sync/ios_chrome_synced_tab_delegate.mm
+++ b/ios/chrome/browser/sync/ios_chrome_synced_tab_delegate.mm
@@ -52,6 +52,11 @@ bool IOSChromeSyncedTabDelegate::IsBeingDestroyed() const {
   return web_state_->IsBeingDestroyed();
 }
 
+// todo(pnoland): add logic to store and return the source tab id on ios.

[Nicolas Zea, 2017/03/20 18:14:50]

reference crbug?

[Patrick Noland, 2017/03/21 22:54:31]

Done.

+SessionID::id_type IOSChromeSyncedTabDelegate::GetSourceTabID() const {
+  return sync_sessions::kInvalidTabID;
+}
+
 std::string IOSChromeSyncedTabDelegate::GetExtensionAppId() const {
   return std::string();
 }