Add update menu item and app menu icon badge

testing/variations/fieldtrial_testing_config_android.json

 {
     "AndroidSessionNotifications": [
         {
             "group_name": "Disabled"
         }
     ],
     "AutodetectEncoding": [
         {
             "group_name": "Enabled"
         }
@@ skipping 321 matching lines @@
     "UMA_EnableCellularLogUpload": [
         {
             "group_name": "Enabled",
             "params": {
                 "Enabled": "true",
                 "Optimize": "true",
                 "Sample_Probability": "50"
             }
         }
     ],
+    "UpdateMenuItem": [
+        {
+            "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"
+            }
+        }

[Steven Holte, 2015/12/16 20:18:36]

You might want to add your Control/Default group here, just for completeness. 
Note that right now only the first group listed here will be tested, so pick the
one you most want testing on.  We may start testing other groups in an FYI
build.

[Theresa, 2015/12/16 22:35:22]

Done.

+    ],
     "VarationsServiceControl": [
         {
             "group_name": "Interval_30min",
             "params": {
                 "fetch_period_min": "30"
             }
         }
     ],
     "WebRTC-LocalIPPermissionCheck": [
         {
             "group_name": "Enabled"
         }
     ],
     "WebRTC-PeerConnectionDTLS1.2": [
         {
             "group_name": "Enabled"
         }
     ]
 }