[Invalidation tracking] Add trace events for layout invalidations

[Invalidation tracking] Add trace events for layout invalidations

This patch adds trace events for setNeedsLayout calls so that we can
do end-to-end tracking of what causes repaints to occur. The devtools
side isn't yet hooked up so this patch simply adds the trace event.

As a cleanup, "core/inspector/InspectorTraceEvents.h" has been moved
up into RenderObject and unneeded includes have been removed.

R=kouhei
BUG=410701
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181865

[pdr., 2014-09-11 22:25:43]

pdr@chromium.org changed reviewers:
+ caseq@chromium.org, kouhei@chromium.org

[kouhei (in TOK), 2014-09-11 22:43:54]

lgtm

Optional Nit: You might want to mention in description that
"core/inspector/InspectorTraceEvents.h" include moved up to RenderObject.h.

[pdr., 2014-09-11 23:15:58]

On 2014/09/11 22:43:54, kouhei wrote:
> lgtm
> 
> Optional Nit: You might want to mention in description that
> "core/inspector/InspectorTraceEvents.h" include moved up to RenderObject.h.

Done. PTAL because I did a minor code change to add a static for the number of
callstack frames to record.

[kouhei (in TOK), 2014-09-11 23:21:30]

On 2014/09/11 23:15:58, pdr wrote:
> On 2014/09/11 22:43:54, kouhei wrote:
> > lgtm
> > 
> > Optional Nit: You might want to mention in description that
> > "core/inspector/InspectorTraceEvents.h" include moved up to RenderObject.h.
> 
> Done. PTAL because I did a minor code change to add a static for the number of
> callstack frames to record.

lgtm

[pdr., 2014-09-11 23:25:21]

The CQ bit was checked by pdr@chromium.org

[commit-bot: I haz the power, 2014-09-11 23:26:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/561413002/40001

[commit-bot: I haz the power, 2014-09-12 01:03:49]

Committed patchset #3 (id:40001) as 181865