Snail on Gmail Loading Page

{
    "update_url": "https:\/\/clients2.google.com\/service\/update2\/crx",
    "name": "Snail on Gmail Loading Page",
    "short_name": "Snail Gmail",
    "description": "We noticed that new Gmail is loading like a snail. Let's watch the crawling snail while it is loading! It's funny, raise your mood!",
    "version": "1.0",
    "homepage_url": "https:\/\/yuragalin.com\/it\/snail-gmail",
    "permissions": [
        "storage",
        "activeTab"
    ],
    "browser_action": {
        "default_icon": "favicon1.png",
        "default_title": "Snail Gmail",
        "default_popup": "popup.html"
    },
    "manifest_version": 2,
    "content_scripts": [
        {
            "matches": [
                "https:\/\/mail.google.com\/*"
            ],
            "all_frames": true,
            "js": [
                "scripts\/content.js"
            ]
        }
    ],
    "web_accessible_resources": [
        "snail-animation.gif"
    ]
}