Check to see that TimelineAgent record types are stable.

Applications outside of WebKit depend on the stability of the mapping of these types to these specific values.

{
    ActivateLayerTree : "ActivateLayerTree"
    BeginFrame : "BeginFrame"
    CancelAnimationFrame : "CancelAnimationFrame"
    CompositeLayers : "CompositeLayers"
    ConsoleTime : "ConsoleTime"
    DecodeImage : "DecodeImage"
    DrawFrame : "DrawFrame"
    EmbedderCallback : "EmbedderCallback"
    EvaluateScript : "EvaluateScript"
    EventDispatch : "EventDispatch"
    FireAnimationFrame : "FireAnimationFrame"
    FunctionCall : "FunctionCall"
    GCEvent : "GCEvent"
    GPUTask : "GPUTask"
    InvalidateLayout : "InvalidateLayout"
    Layout : "Layout"
    MarkDOMContent : "MarkDOMContent"
    MarkFirstPaint : "MarkFirstPaint"
    MarkLoad : "MarkLoad"
    Paint : "Paint"
    PaintSetup : "PaintSetup"
    ParseHTML : "ParseHTML"
    Program : "Program"
    Rasterize : "Rasterize"
    RecalculateStyles : "RecalculateStyles"
    RequestAnimationFrame : "RequestAnimationFrame"
    RequestMainThreadFrame : "RequestMainThreadFrame"
    ResizeImage : "ResizeImage"
    ResourceFinish : "ResourceFinish"
    ResourceReceiveResponse : "ResourceReceiveResponse"
    ResourceReceivedData : "ResourceReceivedData"
    ResourceSendRequest : "ResourceSendRequest"
    Root : "Root"
    ScheduleStyleRecalculation : "ScheduleStyleRecalculation"
    ScrollLayer : "ScrollLayer"
    TimeStamp : "TimeStamp"
    TimerFire : "TimerFire"
    TimerInstall : "TimerInstall"
    TimerRemove : "TimerRemove"
    UpdateCounters : "UpdateCounters"
    UpdateLayerTree : "UpdateLayerTree"
    WebSocketCreate : "WebSocketCreate"
    WebSocketDestroy : "WebSocketDestroy"
    WebSocketReceiveHandshakeResponse : "WebSocketReceiveHandshakeResponse"
    WebSocketSendHandshakeRequest : "WebSocketSendHandshakeRequest"
    XHRLoad : "XHRLoad"
    XHRReadyStateChange : "XHRReadyStateChange"
}