Add update menu item and app menu icon badge

testing/variations/fieldtrial_testing_config_android.json

 {
     "AndroidSessionNotifications": [
         {
             "group_name": "Disabled"
         }
     ],
     "AutofillClassifier": [
         {
             "group_name": "Enabled"
         }
@@ skipping 302 matching lines @@
     "UMA_EnableCellularLogUpload": [
         {
             "group_name": "Enabled",
             "params": {
                 "Enabled": "true",
                 "Optimize": "true",
                 "Sample_Probability": "50"
             }
         }
     ],
+    "UpateMenuItem": [

[gone, 2015/12/08 22:24:24]

*UpdateMenuItem

[Theresa, 2015/12/10 03:53:18]

Done.

+        {
+            "group_name": "Enabled",
+            "params": {
+                "enable_update_menu_item": "true"
+            }
+        },
+        {
+            "group_name": "EnabledWithBadge",
+            "params": {
+                "enable_update_badge": "true",
+                "enable_update_menu_item": "true"
+            }
+        },
+        {
+            "group_name": "EnabledWithSummary",
+            "params": {
+                "enable_update_menu_item": "true",
+                "show_summary": "true"
+            }
+        },
+        {
+            "group_name": "EnabledWithCustomSummary",
+            "params": {
+                "custom_summary": "Custom update summary",
+                "enable_update_menu_item": "true",
+                "show_summary": "true"
+            }
+        }
+    ],
     "VarationsServiceControl": [
         {
             "group_name": "Interval_30min",
             "params": {
                 "fetch_period_min": "30"
             }
         }
     ],
     "WebRTC-LocalIPPermissionCheck": [
         {
             "group_name": "Enabled"
         }
     ],
     "WebRTC-PeerConnectionDTLS1.2": [
         {
             "group_name": "Enabled"
         }
     ]
 }