v8: GCTracer clean-up part 1.

v8: GCTracer clean-up part 1.

- Split GCTracer::~GCTracer into printing functions and update of variables
tracked on Heap.
- Clean-up recording of time, object size and memory size at the beginning and
end of GC.
- Consistently use enum notation in ScopeId.
- Disallow copy and assign for Scope and GCTracer.
- Remove unused stats on GCTracer.

R=hpayer@chromium.org
BUG=

Committed: https://code.google.com/p/v8/source/detail?r=22439

[ernstm, 2014-07-16 11:52:50]

PTAL

[Hannes Payer (out of office), 2014-07-16 13:33:07]

LGTM, just one nit

https://codereview.chromium.org/396893004/diff/20001/src/heap.cc
File src/heap.cc (right):

https://codereview.chromium.org/396893004/diff/20001/src/heap.cc#newcode6042
src/heap.cc:6042: if (FLAG_trace_gc_nvp) {
What about
if (FLAG_trace_gc) {
  if (FLAG_trace_gc_nvp) PrintNVP();
  else Print();
}
and ...

https://codereview.chromium.org/396893004/diff/20001/src/heap.cc#newcode6053
src/heap.cc:6053: if (!FLAG_trace_gc) return;
... drop this check here

https://codereview.chromium.org/396893004/diff/20001/src/heap.cc#newcode6095
src/heap.cc:6095: if (!FLAG_trace_gc) return;
... drop this check here

[ernstm, 2014-07-16 13:43:52]

https://codereview.chromium.org/396893004/diff/20001/src/heap.cc
File src/heap.cc (right):

https://codereview.chromium.org/396893004/diff/20001/src/heap.cc#newcode6042
src/heap.cc:6042: if (FLAG_trace_gc_nvp) {
On 2014/07/16 13:33:06, Hannes Payer wrote:
> What about
> if (FLAG_trace_gc) {
>   if (FLAG_trace_gc_nvp) PrintNVP();
>   else Print();
> }
> and ...

Good catch. This was actually wrong, because the PrintShortHeapStatsistics also
needs to be guarded by the flag.

[ernstm, 2014-07-17 07:51:14]

Committed patchset #4 manually as r22439 (presubmit successful).