Devtools Animations: Remove unused keyframe style information

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 4901 matching lines @@
                     { "name": "name", "type": "string", "optional": true, "description": "CSS keyframed animation's name." },
                     { "name": "keyframes", "type": "array", "items": { "$ref": "KeyframeStyle" }, "description": "List of animation keyframes." }
                 ],
                 "description": "Keyframes Rule"
             },
             {
                 "id": "KeyframeStyle",
                 "type": "object",
                 "properties": [
                     { "name": "offset", "type": "string", "description": "Keyframe's time offset." },
-                    { "name": "style", "$ref": "CSS.CSSStyle", "description": "Keyframe's associated CSS style declaration." },
                     { "name": "easing", "type": "string", "description": "<code>AnimationNode</code>'s timing function." }
                 ],
                 "description": "Keyframe Style"
             }
         ],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables animation domain notifications."
             },
@@ skipping 174 matching lines @@
                 ],
                 "returns": [
                     { "name": "accessibilityNode", "$ref": "AXNode", "description": "The <code>Accessibility.AXNode</code> for this DOM node, if it exists.", "optional": true }
                 ],
                 "description": "Fetches the accessibility node for this DOM node, if it exists.",
                 "hidden": true
             }
         ]
     }]
 }