Add support for ES6 Symbol in heap profiler

Add support for ES6 Symbol in heap profiler

Heap profiler will create a node with name Symbol and type kSymbol.

BUG=chromium:376194
LOG=Y
R=loislo@chromium.org, yangguo@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=21433

[loislo, 2014-05-22 09:12:49]

lgtm

[Yang, 2014-05-22 09:16:51]

https://codereview.chromium.org/290013004/diff/1/src/heap-snapshot-generator.cc
File src/heap-snapshot-generator.cc (right):

https://codereview.chromium.org/290013004/diff/1/src/heap-snapshot-generator....
src/heap-snapshot-generator.cc:856: return AddEntry(object, HeapEntry::kSymbol,
"Symbol");
We seem to use lower case string throughout this method, like "number" for heap
numbers. So maybe we should use lower case here too?

[yurys, 2014-05-22 11:07:02]

https://codereview.chromium.org/290013004/diff/1/src/heap-snapshot-generator.cc
File src/heap-snapshot-generator.cc (right):

https://codereview.chromium.org/290013004/diff/1/src/heap-snapshot-generator....
src/heap-snapshot-generator.cc:856: return AddEntry(object, HeapEntry::kSymbol,
"Symbol");
On 2014/05/22 09:16:51, Yang wrote:
> We seem to use lower case string throughout this method, like "number" for
heap
> numbers. So maybe we should use lower case here too?
I'd rather fix those strings so that they match actual type names. But this
should be addressed in a separate change. Changing Symbol->symbol for
consistency for now.

[Yang, 2014-05-22 11:17:08]

On 2014/05/22 11:07:02, yurys wrote:
>
https://codereview.chromium.org/290013004/diff/1/src/heap-snapshot-generator.cc
> File src/heap-snapshot-generator.cc (right):
> 
>
https://codereview.chromium.org/290013004/diff/1/src/heap-snapshot-generator....
> src/heap-snapshot-generator.cc:856: return AddEntry(object,
HeapEntry::kSymbol,
> "Symbol");
> On 2014/05/22 09:16:51, Yang wrote:
> > We seem to use lower case string throughout this method, like "number" for
> heap
> > numbers. So maybe we should use lower case here too?
> I'd rather fix those strings so that they match actual type names. But this
> should be addressed in a separate change. Changing Symbol->symbol for
> consistency for now.

lgtm.

[yurys, 2014-05-22 11:26:56]

Committed patchset #2 manually as r21433 (presubmit successful).