ES6 symbols: extend V8 API to support symbols

ES6 symbols: extend V8 API to support symbols

Specifically:
- Introduce Symbol and SymbolObject classes.
- Generalise Object::Has and Object::Delete to arbitrary Value-typed keys.
- Generalise some places in the API implementation from String to Name.

It is not possible to intercept symbol-named properties. That is consistent with the idea that symbols are private and should not leak.

R=svenpanne@chromium.org
BUG=v8:2158
Committed: http://code.google.com/p/v8/source/detail?r=14210

[Sven Panne, 2013-04-08 14:04:51]

https://codereview.chromium.org/13626002/diff/3001/include/v8.h
File include/v8.h (right):

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode1481
include/v8.h:1481: static Local<Symbol> New();
Add an Isolate* parameter.

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode1484
include/v8.h:1484: static Local<Symbol> New(const char* data, int length = -1);
Add an Isolate* parameter.

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode1634
include/v8.h:1634: // TODO(1245389): Replace the type-specific versions of these
Does this TODO still make sense?

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode2032
include/v8.h:2032: static Local<Value> New(Handle<Symbol> value);
Add an Isolate* parameter.

https://codereview.chromium.org/13626002/diff/3001/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/13626002/diff/3001/src/api.cc#newcode2464
src/api.cc:2464: return
obj->HasSpecificClassOf(isolate->heap()->Symbol_string());
Can we somehow make this test without the Isolate::Current()? The point is that
the IsDeadChecks will die soon, and we shouldn't rely on the current Isolate.

https://codereview.chromium.org/13626002/diff/3001/src/api.cc#newcode2741
src/api.cc:2741:
ApiCheck(obj->HasSpecificClassOf(isolate->heap()->Symbol_string()),
Same comment as for IsSymbolObject.

[rossberg, 2013-04-09 08:55:23]

https://codereview.chromium.org/13626002/diff/3001/include/v8.h
File include/v8.h (right):

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode1481
include/v8.h:1481: static Local<Symbol> New();
On 2013/04/08 14:04:51, Sven Panne wrote:
> Add an Isolate* parameter.

Done.

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode1484
include/v8.h:1484: static Local<Symbol> New(const char* data, int length = -1);
On 2013/04/08 14:04:51, Sven Panne wrote:
> Add an Isolate* parameter.

Done.

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode1634
include/v8.h:1634: // TODO(1245389): Replace the type-specific versions of these
On 2013/04/08 14:04:51, Sven Panne wrote:
> Does this TODO still make sense?

No, deleted.

https://codereview.chromium.org/13626002/diff/3001/include/v8.h#newcode2032
include/v8.h:2032: static Local<Value> New(Handle<Symbol> value);
On 2013/04/08 14:04:51, Sven Panne wrote:
> Add an Isolate* parameter.

Done.

https://codereview.chromium.org/13626002/diff/3001/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/13626002/diff/3001/src/api.cc#newcode2464
src/api.cc:2464: return
obj->HasSpecificClassOf(isolate->heap()->Symbol_string());
On 2013/04/08 14:04:51, Sven Panne wrote:
> Can we somehow make this test without the Isolate::Current()? The point is
that
> the IsDeadChecks will die soon, and we shouldn't rely on the current Isolate.

As discussed offline, keeping it like this for now for consistency with other
test functions. Needs more general clean-up.

https://codereview.chromium.org/13626002/diff/3001/src/api.cc#newcode2741
src/api.cc:2741:
ApiCheck(obj->HasSpecificClassOf(isolate->heap()->Symbol_string()),
On 2013/04/08 14:04:51, Sven Panne wrote:
> Same comment as for IsSymbolObject.

Same here.

[Sven Panne, 2013-04-09 09:02:30]

lgtm

[rossberg, 2013-04-10 12:16:43]

Committed patchset #4 manually as r14210 (presubmit successful).