[MD History] Add UMA stats for switching views and the CBD button.

chrome/test/data/webui/md_history/history_synced_tabs_test.js

Index: chrome/test/data/webui/md_history/history_synced_tabs_test.js
diff --git a/chrome/test/data/webui/md_history/history_synced_tabs_test.js b/chrome/test/data/webui/md_history/history_synced_tabs_test.js
index 1aaa566fe0995204f3a5cb2be6104e11a05e8128..5d8d9d533481fb3c2e06f18e93cabfc1a6b517a5 100644
--- a/chrome/test/data/webui/md_history/history_synced_tabs_test.js
+++ b/chrome/test/data/webui/md_history/history_synced_tabs_test.js
@@ -53,7 +53,7 @@ cr.define('md_history.history_synced_tabs_test', function() {
 
       setup(function() {
         element = document.createElement('history-synced-device-manager');
-        element.updateSignInState(true);
+        element.signInState = true;
         element.searchTerm = '';
         replaceBody(element);
       });
@@ -214,10 +214,10 @@ cr.define('md_history.history_synced_tabs_test', function() {
       });
 
       test('show sign in promo', function() {
-        element.updateSignInState(false);
+        element.signInState = false;
         return flush().then(function() {
           assertFalse(element.$['sign-in-guide'].hidden);
-          element.updateSignInState(true);
+          element.signInState = true;
           return flush();
         }).then(function() {
           assertTrue(element.$['sign-in-guide'].hidden);
@@ -226,7 +226,7 @@ cr.define('md_history.history_synced_tabs_test', function() {
 
       test('no synced tabs message', function() {
         // When user is not logged in, there is no synced tabs.
-        element.signInState_ = false;
+        element.signInState = false;
         element.syncedDevices_ = [];
         return flush().then(function() {
           assertTrue(element.$['no-synced-tabs'].hidden);
@@ -234,7 +234,7 @@ cr.define('md_history.history_synced_tabs_test', function() {
           var cards = getCards(element);
           assertEquals(0, cards.length);
 
-          element.updateSignInState(true);
+          element.signInState = true;
 
           return flush();
         }).then(function() {
@@ -265,7 +265,7 @@ cr.define('md_history.history_synced_tabs_test', function() {
           // If there are any synced tabs, hide the 'no synced tabs' message.
           assertTrue(element.$['no-synced-tabs'].hidden);
 
-          element.updateSignInState(false);
+          element.signInState = false;
           return flush();
         }).then(function() {
           // When user signs out, don't show the message.