First part of PAGE_TRANSITION_START_PAGE cleanup.

chrome/common/extensions/api/history.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": "history",
     "types": [
       {
         "id": "HistoryItem",
@@ skipping 12 matching lines @@
         "id": "VisitItem",
         "type": "object",
         "description": "An object encapsulating one visit to a URL.",
         "properties": {
           "id": {"type": "string", "minimum": 0, "description": "The unique identifier for the item."},
           "visitId": {"type": "string", "description": "The unique identifier for this visit."},
           "visitTime": {"type": "number", "optional": true, "description": "When this visit occurred, represented in milliseconds since the epoch."},
           "referringVisitId": {"type": "string", "description": "The visit ID of the referrer."},
           "transition": {
             "type": "string",
-            "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "start_page", "form_submit", "reload", "keyword", "keyword_generated"],
+            "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "auto_toplevel", "form_submit", "reload", "keyword", "keyword_generated"],
             "description": "The <a href='#transition_types'>transition type</a> for this visit from its referrer."
           }
         }
       }
     ],
     "functions": [
       {
         "name": "search",
         "type": "function",
         "description": "Searches the history for the last visit time of each page matching the query.",
@@ skipping 127 matching lines @@
             "properties": {
               "allHistory": { "type": "boolean", "description": "True if all history was removed.  If true, then urls will be empty." },
               "urls": { "type": "array", "items": { "type": "string" }, "optional": true}
             }
           }
         ]
       }
     ]
   }
 ]