MD History: Hide sign in guide in guest mode

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 5a47f0a9c2deccb0e168d83aaddc0fa31cf71689..94276c8aab7d7956bba9e2e7295ca7a7225da03f 100644
--- a/chrome/browser/resources/md_history/synced_device_manager.js
+++ b/chrome/browser/resources/md_history/synced_device_manager.js
@@ -45,6 +45,12 @@ Polymer({
     },
 
     /** @private */
+    guestSession_: {
+      type: Boolean,
+      value: loadTimeData.getBoolean('isGuestSession'),
+    },
+
+    /** @private */
     fetchingSyncedTabs_: {
       type: Boolean,
       value: false,
@@ -111,10 +117,21 @@ Polymer({
    * @return {boolean}
    */
   showNoSyncedMessage: function(signInState, syncedDevicesLength) {
+    if (this.guestSession_)
+      return true;

[calamity, 2016/07/21 04:56:49]

nit: Newline after early return.

[lshang, 2016/07/21 07:09:55]

Done.

     return signInState && syncedDevicesLength == 0;
   },
 
   /**
+   * Decide whether or not should hide sign in guide.

[calamity, 2016/07/21 04:56:49]

* Hides the signin guide when the user is already signed in or in a guest
session.

[lshang, 2016/07/21 07:09:55]

Done.

+   * @param {boolean} signInState
+   * @return {boolean}
+   */
+  hideSignInGuide: function(signInState) {

[calamity, 2016/07/21 04:56:49]

Maybe make this 'showSignInGuide' and invert everything. That would be
consistent with showNoSyncedMessage above.

[lshang, 2016/07/21 07:09:55]

Done. Yeah I was also thinking of this, this is probably better:-)

+    return signInState || this.guestSession_;
+  },
+
+  /**
    * Decide what message should be displayed when user is logged in and there
    * are no synced tabs.
    * @param {boolean} fetchingSyncedTabs