[Sync] Removing complexity around PROXY_TABS now that empty sessions are provided when disabled.

chrome/browser/resources/md_history/synced_device_manager.js

Index: chrome/browser/resources/md_history/synced_device_manager.js
diff --git a/chrome/browser/resources/md_history/synced_device_manager.js b/chrome/browser/resources/md_history/synced_device_manager.js
index 8ad6a70f051a65381a9d92f05a92db61f5e45bbf..6dd7f7881bc2bb6b6a4acfffe6ed9d24b49dd500 100644
--- a/chrome/browser/resources/md_history/synced_device_manager.js
+++ b/chrome/browser/resources/md_history/synced_device_manager.js
@@ -267,14 +267,6 @@ Polymer({
   },
 
   /**
-   * End fetching synced tabs when sync is disabled.
-   */
-  tabSyncDisabled: function() {
-    this.fetchingSyncedTabs_ = false;
-    this.clearDisplayedSyncedDevices_();
-  },
-
-  /**
    * Get called when user's sign in state changes, this will affect UI of synced
    * tabs page. Sign in promo gets displayed when user is signed out, and
    * different messages are shown when there are no synced tabs.