Implementing TabManager extensions API Discard Function.

chrome/common/extensions/api/tabs.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace": "tabs",
     "description": "Use the <code>chrome.tabs</code> API to interact with the browser's tab system. You can use this API to create, modify, and rearrange tabs in the browser.",
     "types": [
       { "id": "MutedInfoReason",
@@ skipping 889 matching lines @@
             "description": "Called with the tab's current zoom settings.",
             "parameters": [
               {
                 "$ref": "ZoomSettings",
                 "name": "zoomSettings",
                 "description": "The tab's current zoom settings."
               }
             ]
           }
         ]
+      },
+      {
+        "name": "discard",
+        "type": "function",
+        "description": "Discards a tab from memory. Discarded tabs are still visible on the tab strip and are reloaded when activated.",
+        "parameters": [
+          {
+            "type": "integer",
+            "name": "tabId",
+            "optional": true,
+            "minimum": 0,
+            "description": "The ID of the tab to be discarded. If specified, the tab will be discarded unless it's active or already discarded. If omitted, the browser will discard the least important tab. This can fail if no discardable tabs exist."
+          },
+          {
+            "type": "function",
+            "name": "callback",
+            "optional": true,
+            "description": "Called after the operation is completed.",
+            "parameters": [
+              {
+                "name": "tab",
+                "$ref": "Tab",
+                "optional": true,
+                "description": "Discarded tab if it was successfully discarded. Undefined otherwise."
+              }
+            ]
+          }
+        ]
       }
     ],
     "events": [
       {
         "name": "onCreated",
         "type": "function",
         "description": "Fired when a tab is created. Note that the tab's URL may not be set at the time this event fired, but you can listen to onUpdated events to be notified when a URL is set.",
         "parameters": [
           {
             "$ref": "Tab",
@@ skipping 264 matching lines @@
             "tabId": {"type": "integer", "minimum": 0},
             "oldZoomFactor": {"type": "number"},
             "newZoomFactor": {"type": "number"},
             "zoomSettings": {"$ref": "ZoomSettings"}
           }
         }]
       }
     ]
   }
 ]