Add support for a "frame" context option to chrome.contextMenus.create/update.

chrome/common/extensions/api/extension_api.json

Index: chrome/common/extensions/api/extension_api.json
diff --git a/chrome/common/extensions/api/extension_api.json b/chrome/common/extensions/api/extension_api.json
index 936792791180a806d71573915513b48c4f76b47c..f62312561eb822835f2672473815821f8141ff93 100644
--- a/chrome/common/extensions/api/extension_api.json
+++ b/chrome/common/extensions/api/extension_api.json
@@ -2834,7 +2834,7 @@
                 "items": {"type": "string"},
                 "minItems": 1,
                 "optional": true,
-                "description": "List of contexts this menu item will appear in. Legal values are: 'all', 'page', 'selection', 'link', 'editable', 'image', 'video', and 'audio'. Defaults to ['page']."
+                "description": "List of contexts this menu item will appear in. Legal values are: 'all', 'page', 'frame', 'selection', 'link', 'editable', 'image', 'video', and 'audio'. Defaults to ['page']."

[asargent_no_longer_on_chrome, 2011/04/06 20:39:33]

Some time after I first added the contextMenus API, we added an "enum"
capability but I forgot to convert over to using it here. If you want to it
would be cool to convert over to using an enum here instead of a string. That
way callers will get errors at call time from our dispatcher code if for
instance they misspell 'editable' or whatever, instead of having it just not
work right. 

[Mihai Parparita -not on Chrome, 2011/04/06 21:01:05]

Will do this in a follow-up CL.

               },
               "onclick": {
                 "type": "function",