Chrome extension placeholder value for manifest field - google-chrome

Question

I was wondering if it was possible to set a 'placeholder' value for a field in the manifest.json file of a Chrome extension. For example, I just started a new extension and my manifest looks like this :
{
"manifest_version": 2,
"author" : "My Name",
"name": "Extension Name",
"version": "0.0.1",
"description": "Desc",
"icons": { "16": "icon16.png",
"48": "icon48.png",
"128": "icon128.png" },
"browser_action" : {
"default_title" : "Extension",
"default_icon" : {
"16": "icon32.png",
"48": "icon48.png",
"128": "icon128.png"
},
"default_popup" : "dropdown.html",
"js" : ["dropdown.js"]
},
"content_scripts" : [ {
"matches" : ["http://*/*, https://*/*"],
"js" : ["some_script.js"]
} ]
}
However, I have not yet made the icno*.png files so, obviously, whenever trying to load the extension, chrome says that it can't find the icon files.
Can I do something like :
//[...]
"default_icon" : {
//Will be added later
},
//[...]
or do I have to just delete the "browser_icon" and "icons" fields and add them later?
I found nothing in the Official Google Documentation.

Answer 1

In general, placeholder values are not permitted in the manifest.json. Many of the fields are checked for validity and/or that the resource is available when the manifest.json is loaded. This is necessary because these values are immediately used. Thus, they must be valid. The checking includes verifying the icon files for the browser_action and page_action keys. These files must exist for the extension to be loaded. Overall, what is required to be resolved, in order for the manifest.json to load, is explicitly stated in the error displayed when you attempt to load the unpacked extension from chrome://extensions/. You will need to resolve all errors in order for the extension to be loaded.
For icon files, you can usually delete the reference, or provide a placeholder icon file that contains an actual graphic. Personally, I just copy one of an assortment of icons I generally use, which are in the public domain, into a generically named icon file (e.g. icon.png, or myIcon.png, etc.). If you want, you could do a search for public domain icons which you could use for this purpose. There are a lot of choices.