AutoDiscardable property support on Chrome Extensions Tabs API.

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 34 matching lines @@
           // TODO(kalman): Investigate how this is ending up as -1 (based on window type? a bug?) and whether it should be optional instead.
           "index": {"type": "integer", "minimum": -1, "description": "The zero-based index of the tab within its window."},
           "windowId": {"type": "integer", "minimum": 0, "description": "The ID of the window the tab is contained within."},
           "openerTabId": {"type": "integer", "minimum": 0, "optional": true, "description": "The ID of the tab that opened this tab, if any. This property is only present if the opener tab still exists."},
           "selected": {"type": "boolean", "description": "Whether the tab is selected.", "deprecated": "Please use $(ref:tabs.Tab.highlighted)."},
           "highlighted": {"type": "boolean", "description": "Whether the tab is highlighted."},
           "active": {"type": "boolean", "description": "Whether the tab is active in its window. (Does not necessarily mean the window is focused.)"},
           "pinned": {"type": "boolean", "description": "Whether the tab is pinned."},
           "audible": {"type": "boolean", "optional": true, "description": "Whether the tab has produced sound over the past couple of seconds (but it might not be heard if also muted). Equivalent to whether the speaker audio indicator is showing."},
           "discarded": {"type": "boolean", "description": "Whether the tab is discarded. A discarded tab is one whose content has been unloaded from memory, but is still visible in the tab strip. Its content gets reloaded the next time it's activated."},
+          "autoDiscardable":  {"type": "boolean", "description": "Whether the tab is auto-discardable. An auto-discardable tab is eligible for discarding when memory resources are low."},

[Devlin, 2016/08/02 22:48:14]

Saying "whether the tab is auto-discardable. <definition of auto-discardable>"
could probably be replaced here with "whether the tab is <definition of
auto-discardable>".  Also, aren't non-auto-discardable tabs eligible for
discarding from the discard() method?  If so, maybe we should change this to
something like "can be discarded automatically by the browser when resources are
low."

[Anderson Silva, 2016/08/03 14:47:41]

Yes, you're right, non-auto-discardable tabs can be discarded by discard(). I'll
update the description.

           "mutedInfo": {"$ref": "MutedInfo", "optional": true, "description": "Current tab muted state and the reason for the last state change."},
           "url": {"type": "string", "optional": true, "description": "The URL the tab is displaying. This property is only present if the extension's manifest includes the <code>\"tabs\"</code> permission."},
           "title": {"type": "string", "optional": true, "description": "The title of the tab. This property is only present if the extension's manifest includes the <code>\"tabs\"</code> permission."},
           "favIconUrl": {"type": "string", "optional": true, "description": "The URL of the tab's favicon. This property is only present if the extension's manifest includes the <code>\"tabs\"</code> permission. It may also be an empty string if the tab is loading."},
           "status": {"type": "string", "optional": true, "description": "Either <em>loading</em> or <em>complete</em>."},
           "incognito": {"type": "boolean", "description": "Whether the tab is in an incognito window."},
           "width": {"type": "integer", "optional": true, "description": "The width of the tab in pixels."},
           "height": {"type": "integer", "optional": true, "description": "The height of the tab in pixels."},
           "sessionId": {"type": "string", "optional": true, "description": "The session ID used to uniquely identify a Tab obtained from the $(ref:sessions) API."}
         }
@@ skipping 379 matching lines @@
                 "description": "Whether the tabs are muted."
               },
               "highlighted": {
                 "type": "boolean",
                 "optional": true,
                 "description": "Whether the tabs are highlighted."
               },
               "discarded": {
                 "type": "boolean",
                 "optional": true,
-                "description": "Whether the tab is discarded. A discarded tab is one whose content has been unloaded from memory, but is still visible in the tab strip. Its content gets reloaded the next time it's activated."
+                "description": "Whether the tabs are discarded. A discarded tab is one whose content has been unloaded from memory, but is still visible in the tab strip. Its content gets reloaded the next time it's activated."
+              },
+              "autoDiscardable": {
+                "type": "boolean",
+                "optional": true,
+                "description": "Whether the tabs are auto-discardable. An auto-discardable tab is eligible for discarding when memory resources are low."
               },
               "currentWindow": {
                 "type": "boolean",
                 "optional": true,
                 "description": "Whether the tabs are in the <a href='windows#current-window'>current window</a>."
               },
               "lastFocusedWindow": {
                 "type": "boolean",
                 "optional": true,
                 "description": "Whether the tabs are in the last focused window."
@@ skipping 133 matching lines @@
               "muted": {
                 "type": "boolean",
                 "optional": true,
                 "description": "Whether the tab should be muted."
               },
               "openerTabId": {
                 "type": "integer",
                 "minimum": 0,
                 "optional": true,
                 "description": "The ID of the tab that opened this tab. If specified, the opener tab must be in the same window as this tab."
+              },
+              "autoDiscardable": {
+                "type": "boolean",
+                "optional": true,
+                "description": "Whether the tab should be auto-discardable. An auto-discardable tab is eligible for discarding when memory resources are low."
               }
             }
           },
           {
             "type": "function",
             "name": "callback",
             "optional": true,
             "parameters": [
               {
                 "name": "tab",
@@ skipping 361 matching lines @@
               "audible": {
                 "type": "boolean",
                 "optional": true,
                 "description": "The tab's new audible state."
               },
               "discarded": {
                 "type": "boolean",
                 "optional": true,
                 "description": "The tab's new discarded state."
               },
+              "autoDiscardable": {
+                "type": "boolean",
+                "optional": true,
+                "description": "The tab's new auto-discardable state."
+              },
               "mutedInfo": {
                 "$ref": "MutedInfo",
                 "optional": true,
                 "description": "The tab's new muted state and the reason for the change."
               },
               "favIconUrl": {
                 "type": "string",
                 "optional": true,
                 "description": "The tab's new favicon URL."
               },
@@ skipping 218 matching lines @@
             "tabId": {"type": "integer", "minimum": 0},
             "oldZoomFactor": {"type": "number"},
             "newZoomFactor": {"type": "number"},
             "zoomSettings": {"$ref": "ZoomSettings"}
           }
         }]
       }
     ]
   }
 ]