Removing chrome.pushMessaging API

chrome/common/extensions/docs/templates/json/intro_tables.json

 {
   "alarms": {
     "Learn More": [
       {
         "link": "event_pages",
         "text": "Event Pages"
       }
     ]
   },
   "app_runtime": {
@@ skipping 180 matching lines @@
     ]
   },
   "permissions": {
     "Learn More": [
       {
         "link": "declare_permissions",
         "text": "Declaring permissions"
       }
     ]
   },
-  "pushMessaging": {
-    "Learn More": [
-      {
-        "link": "cloudMessagingV1",
-        "text": "Google Cloud Messaging for Chrome"
-      },
-      {
-        "link": "gcm_server",
-        "text": "API Reference for GCM service"
-      }
-    ]
-  },
   "runtime": {
     "Learn More": [
       {
         "link": "app_lifecycle",
         "text": "Manage App Lifecycle",
         "extension_types": ["platform_app"]
       },
       {
         "link": "event_pages",
         "text": "Event Pages"
@@ skipping 105 matching lines @@
     ]
   },
   "windows": {
     "Permissions": [
       {
         "partial": "intro_tables/windows_permissions.html"
       }
     ]
   }
 }