Tests Timeline events emitted when idle callback is scheduled and fired.

RequestIdleCallback Properties:
{
    data : {
        frame : <string>
        id : <number>
        stackTrace : <object>
        timeout : 0
    }
    endTime : <number>
    frameId : <string>
    stackTrace : <object>
    startTime : <number>
    type : "RequestIdleCallback"
}
Text details for RequestIdleCallback: idle-callback.html:10
RequestIdleCallback Properties:
{
    data : {
        frame : <string>
        id : <number>
        stackTrace : <object>
        timeout : 0
    }
    endTime : <number>
    frameId : <string>
    stackTrace : <object>
    startTime : <number>
    type : "RequestIdleCallback"
}
Text details for RequestIdleCallback: idle-callback.html:12
RequestIdleCallback Properties:
{
    data : {
        frame : <string>
        id : <number>
        stackTrace : <object>
        timeout : 0
    }
    endTime : <number>
    frameId : <string>
    stackTrace : <object>
    startTime : <number>
    type : "RequestIdleCallback"
}
Text details for RequestIdleCallback: idle-callback.html:15
CancelIdleCallback Properties:
{
    data : {
        frame : <string>
        id : <number>
        stackTrace : <object>
    }
    endTime : <number>
    frameId : <string>
    stackTrace : <object>
    startTime : <number>
    type : "CancelIdleCallback"
}
Text details for CancelIdleCallback: idle-callback.html:11
FireIdleCallback Properties:
{
    data : {
        allottedMilliseconds : <number>
        frame : <string>
        id : <number>
        timedOut : <boolean>
    }
    endTime : <number>
    frameId : <string>
    startTime : <number>
    type : "FireIdleCallback"
}
Text details for FireIdleCallback: idle-callback.html:12
FireIdleCallback Properties:
{
    data : {
        allottedMilliseconds : <number>
        frame : <string>
        id : <number>
        timedOut : <boolean>
    }
    endTime : <number>
    frameId : <string>
    startTime : <number>
    type : "FireIdleCallback"
}
Text details for FireIdleCallback: idle-callback.html:15
FireIdleCallback has a warning

