Fix an out-of-date issue in chrome.webNavigation document.

chrome/common/extensions/api/web_navigation.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": "webNavigation",
     "description": "Use the <code>chrome.webNavigation</code> API to receive notifications about the status of navigation requests in-flight.",
     "types": [],
     "functions": [
@@ skipping 131 matching lines @@
         ],
         "parameters": [
           {
             "type": "object",
             "name": "details",
             "properties": {
               "tabId": {"type": "integer", "description": "The ID of the tab in which the navigation occurs."},
               "url": {"type": "string"},
               "processId": {"type": "integer", "description": "The ID of the process runs the renderer for this tab."},
               "frameId": {"type": "integer", "description": "0 indicates the navigation happens in the tab content window; a positive value indicates navigation in a subframe. Frame IDs are unique within a tab."},
-              "transitionType": {"type": "string", "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "start_page", "form_submit", "reload", "keyword", "keyword_generated"], "description": "Cause of the navigation. The same transition types as defined in the history API are used."},
+              "transitionType": {"type": "string", "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "auto_toplevel", "form_submit", "reload", "keyword", "keyword_generated"], "description": "Cause of the navigation. The same transition types as defined in the history API are used."},

[not at google - send to devlin, 2014/01/17 22:16:02]

yeah we can't just remove "start_page" for backwards compatibility. We could
however go from

...
"generated",
"start_page",
"form_submit",
...

to

...
"generated",
{"name": "start_page", "nodoc": true}
"auto_toplevel",
"form_submit",
...


and see how that turns out. Then like Jochen says maintain compatibility by
mapping from start_page to auto_toplevel somewhere.

[Haojian Wu, 2014/01/18 04:11:35]

After looking through the code, I think here is just a document issue(The doc
description is not the same with the actual result).

From Roger@'s words and his replaced
CL(https://codereview.chromium.org/10897034/), he just replaced START_PAGE with
AUTO_TOPLEVEL, keeping same functionality. So the returned 'transitionType' is
'auto_toplevel' instead of 'start_page' now(see
https://code.google.com/p/chromium/codesearch#chromium/src/content/public/com...).

               "transitionQualifiers": {"type": "array", "description": "A list of transition qualifiers.", "items": {"type": "string", "enum": ["client_redirect", "server_redirect", "forward_back", "from_address_bar"]}},
               "timeStamp": {"type": "number", "description": "The time when the navigation was committed, in milliseconds since the epoch."}
             }
           }
         ]
       },
       {
         "name": "onDOMContentLoaded",
         "type": "function",
         "description": "Fired when the page's DOM is fully constructed, but the referenced resources may not finish loading.",
@@ skipping 113 matching lines @@
         ],
         "parameters": [
           {
             "type": "object",
             "name": "details",
             "properties": {
               "tabId": {"type": "integer", "description": "The ID of the tab in which the navigation occurs."},
               "url": {"type": "string"},
               "processId": {"type": "integer", "description": "The ID of the process runs the renderer for this tab."},
               "frameId": {"type": "integer", "description": "0 indicates the navigation happens in the tab content window; a positive value indicates navigation in a subframe. Frame IDs are unique within a tab."},
-              "transitionType": {"type": "string", "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "start_page", "form_submit", "reload", "keyword", "keyword_generated"], "description": "Cause of the navigation. The same transition types as defined in the history API are used."},
+              "transitionType": {"type": "string", "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "auto_toplevel", "form_submit", "reload", "keyword", "keyword_generated"], "description": "Cause of the navigation. The same transition types as defined in the history API are used."},
               "transitionQualifiers": {"type": "array", "description": "A list of transition qualifiers.", "items": {"type": "string", "enum": ["client_redirect", "server_redirect", "forward_back", "from_address_bar"]}},
               "timeStamp": {"type": "number", "description": "The time when the navigation was committed, in milliseconds since the epoch."}
             }
           }
         ]
       },
       {
         "name": "onTabReplaced",
         "type": "function",
         "description": "Fired when the contents of the tab is replaced by a different (usually previously pre-rendered) tab.",
@@ skipping 23 matching lines @@
         ],
         "parameters": [
           {
             "type": "object",
             "name": "details",
             "properties": {
               "tabId": {"type": "integer", "description": "The ID of the tab in which the navigation occurs."},
               "url": {"type": "string"},
               "processId": {"type": "integer", "description": "The ID of the process runs the renderer for this tab."},
               "frameId": {"type": "integer", "description": "0 indicates the navigation happens in the tab content window; a positive value indicates navigation in a subframe. Frame IDs are unique within a tab."},
-              "transitionType": {"type": "string", "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "start_page", "form_submit", "reload", "keyword", "keyword_generated"], "description": "Cause of the navigation. The same transition types as defined in the history API are used."},
+              "transitionType": {"type": "string", "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "auto_toplevel", "form_submit", "reload", "keyword", "keyword_generated"], "description": "Cause of the navigation. The same transition types as defined in the history API are used."},
               "transitionQualifiers": {"type": "array", "description": "A list of transition qualifiers.", "items": {"type": "string", "enum": ["client_redirect", "server_redirect", "forward_back", "from_address_bar"]}},
               "timeStamp": {"type": "number", "description": "The time when the navigation was committed, in milliseconds since the epoch."}
             }
           }
         ]
       }
     ]
   }
 ]