Revert of TimelinePanel: convert another portion of getters on TimelineModel.Record into functions (https://codereview.chromium.org/251783002/)

Reason for revert:
This will break tests as per try jobs. Why do you commit manually without testing?

Original issue's description:
> TimelinePanel: convert another portion of getters on TimelineModel.Record into functions
> 
> Mechanical change. No business logic changes.
> thread, type, frameId, stackTrace and aggregatedStats were converted.
> 
> BUG=361045
> R=yurys@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=172621
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=172730

TBR=yurys@chromium.org,loislo@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=361045

Review URL: https://codereview.chromium.org/258713013

git-svn-id: svn://svn.chromium.org/blink/trunk@172731 bbb929c8-8fbe-4397-9dbb-9b2b20218538