Set Extension Infobars to have a fixed height determined by the developer (clamped to sane min an...

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "unprivileged": true,
     "types": [
       {
         "id": "MessageSender",
         "type": "object",
         "description": "An object containing information about the script context that sent a message or request.",
         "properties": {
@@ skipping 2144 matching lines @@
             "name": "details",
             "type": "object",
             "properties": {
               "tabId": {
                 "type": "integer",
                 "description": "The tab id for the tab to display the infobar in."
               },
               "path": {
                 "type": "string",
                 "description": "The html file that contains the infobar."
+              },
+              "height": {
+                "type": "integer",
+                "description": "The height (in pixels) of the infobar to show. If omitted, the default infobar height will be used.",
+                "optional": true,
+                "minimum": 0,
+                "maximum": 72
               }
             }
           },
           {
             "type": "function",
             "name": "callback",
             "optional": true,
             "parameters": [
               {
                 "name": "window", "$ref": "Window", "description": "Contains details about the window in which the infobar was created."
@@ skipping 5352 matching lines @@
                 "description": "A string result code. The value is non-empty on success only in tests.",
                 "optional": "true"
               }
             ]
           }
         ]
       }
     ]
   }
 ]