function buildPlatformExtensionAPI(extensionInfo, inspectedTabId)
{
    return "var extensionInfo = " + JSON.stringify(extensionInfo) + ";" +
       "var tabId = " + inspectedTabId + ";" +
       platformExtensionAPI.toString();
}
@param {!ExtensionDescriptor} extensionInfo
@param {string} inspectedTabId
@return {string}