Timeline: fix reset logic of TracingTimelineModel & co

Timeline: fix reset logic of TracingTimelineModel & co

The way we perform reset (i.e. clear records) was
badly wrong in a couple of places:
 - we generally should only reset the objects that we own,
so TimelineTracingView should have not tried to reset TracingModel;
 - TracingTimelineModel should reset before the record is
started,not after.

BUG=361045
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=175810

[loislo, 2014-06-09 16:40:34]

lgtm

[commit-bot: I haz the power, 2014-06-09 16:41:44]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/caseq@chromium.org/326693002/1

[caseq, 2014-06-09 16:52:22]

The CQ bit was unchecked by caseq@chromium.org

[caseq, 2014-06-09 16:53:21]

The CQ bit was checked by caseq@chromium.org

[commit-bot: I haz the power, 2014-06-09 16:53:45]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/caseq@chromium.org/326693002/1

[commit-bot: I haz the power, 2014-06-09 17:56:46]

Change committed as 175810

[yurys, 2014-06-10 07:04:27]

https://codereview.chromium.org/326693002/diff/1/Source/devtools/front_end/ti...
File Source/devtools/front_end/timeline/TracingTimelineModel.js (right):

https://codereview.chromium.org/326693002/diff/1/Source/devtools/front_end/ti...
Source/devtools/front_end/timeline/TracingTimelineModel.js:104: this.reset();
This should go into _startRecordingWithCategories