Fix an out-of-date issue in chrome.webNavigation document.

chrome/common/extensions/api/web_navigation.json

Index: chrome/common/extensions/api/web_navigation.json
diff --git a/chrome/common/extensions/api/web_navigation.json b/chrome/common/extensions/api/web_navigation.json
index 783ecdddee03f9215b32b2b97c27008c0d85f54e..493e51f8665a4d8f2831a3b2b08ba91f16680eb1 100644
--- a/chrome/common/extensions/api/web_navigation.json
+++ b/chrome/common/extensions/api/web_navigation.json
@@ -149,7 +149,7 @@
               "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", "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. For backward compatibility, \"start_page\" is the sames as \"auto_toplevel\" in the history API."},

[not at google - send to devlin, 2014/01/22 15:23:50]

why are all these comments necessary? auto_toplevel isn't exposed to the
extension in any way.

[Haojian Wu, 2014/01/22 15:59:24]

But as the document says "The same transition types as defined in the history
API are used.", in history API doc "auto_toplevel" is exposed to extensions.
see(https://developer.chrome.com/extensions/history.html)

[not at google - send to devlin, 2014/01/22 16:06:35]

Ugh. Interesting. Looks like this was changed in
https://chromiumcodereview.appspot.com/10897034 in the exact same manner as this
CL is trying to change; except that CL was not reviewed by an extensions owner.
Damn... well, that's a shame.

Ok, anyway, thanks for pointing that out. We should actually make those enums
point at the same thing but it's not worth doing now (nor probably... ever,
given they've now diverged). In that case I have a suggestion re wording; it
should be "same as" not "sames as", but I would go further:

"These are the same transition types as defined in the $ref:[history.VisitedItem
History API] except with <code>\"start_page\"</code> in place of
<code>\"auto_toplevel\"</code> (for backwards compatibility)."

(for all such comments)

[Haojian Wu, 2014/01/23 06:44:28]

Done.

               "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."}
             }
@@ -283,7 +283,7 @@
               "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", "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. For backward compatibility, \"start_page\" is the sames as \"auto_toplevel\" in the history API."},
               "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."}
             }
@@ -327,7 +327,7 @@
               "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", "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. For backward compatibility, \"start_page\" is the sames as \"auto_toplevel\" in the history API."},
               "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."}
             }