Add deletion to the activityLogPrivate API

chrome/common/extensions/api/activity_log_private.json

 // Copyright 2013 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": "activityLogPrivate",
     "description": "none",
     "types": [
       {
@@ skipping 49 matching lines @@
             "name": "callback",
             "type": "function",
             "parameters": [
               {
                 "name": "result",
                 "$ref": "ActivityResultSet"
               }
             ]
           }
         ]
+      },
+      {
+        "name": "deleteDatabase",
+        "type": "function",
+        "description": "Deletes the entire ActivityLog database.",
+        "parameters": []
+      },
+      {
+        "name": "deleteUrls",
+        "type": "function",
+        "description": "Delete URLs in the ActivityLog database.",
+        "parameters": [
+          {
+            "name": "urls",
+            "type": "array",
+            "items": { "type": "string" },
+            "description": "Erases only the URLs listed; if empty, erases all URLs.",
+            "optional": true
+          }
+        ]
       }
     ],
     "events": [
       {
         "name": "onExtensionActivity",
         "type": "function",
         "description": "Fired when a given extension performs another activity.",
         "parameters": [
           {
             "name": "activity",
             "$ref": "ExtensionActivity"
           }
         ]
       }
     ]
   }
 ]