Changes to prepare for allowing script snapshots to be taken after running the main application

Changes to prepare for allowing script snapshots to be taken after running the main application
 - Create singleton empty context scope object
 - Add an implicit field in the context scope so we can distinguish implict context scope objects
 - Allow serialization of extractor_parameter_types, extractor_parameter_names

BUG=
R=regis@google.com

Committed: https://github.com/dart-lang/sdk/commit/6b2ae767fd40faa7a07f10f1891494aada427878

[siva, 2015-08-31 20:10:19]

asiva@google.com changed reviewers:
+ regis@google.com

[regis, 2015-08-31 20:25:06]

LGTM

I finally understood that is_implicit means "is the context scope of an implicit
closure".

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/object.h
File runtime/vm/object.h (right):

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/object.h#new...
runtime/vm/object.h:4472: // level is assigned.
Can you update this comment with the meaning of is_implicit?

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/raw_object.h
File runtime/vm/raw_object.h (right):

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/raw_object.h...
runtime/vm/raw_object.h:1314: bool is_implicit_;
Add a comment (so far in the review, I still do not understand what is_implicit
means).

[siva, 2015-08-31 22:20:52]

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/object.h
File runtime/vm/object.h (right):

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/object.h#new...
runtime/vm/object.h:4472: // level is assigned.
On 2015/08/31 20:25:06, regis wrote:
> Can you update this comment with the meaning of is_implicit?

Done.

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/raw_object.h
File runtime/vm/raw_object.h (right):

https://codereview.chromium.org/1323813004/diff/40001/runtime/vm/raw_object.h...
runtime/vm/raw_object.h:1314: bool is_implicit_;
On 2015/08/31 20:25:06, regis wrote:
> Add a comment (so far in the review, I still do not understand what
is_implicit
> means).

Done.

[siva, 2015-08-31 22:41:45]

Committed patchset #4 (id:60001) manually as
6b2ae767fd40faa7a07f10f1891494aada427878 (presubmit successful).

[rmacnak, 2015-09-02 01:19:50]

rmacnak@google.com changed reviewers:
+ rmacnak@google.com

[rmacnak, 2015-09-02 01:19:50]

J'accuse!

https://codereview.chromium.org/1323813004/diff/60001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1323813004/diff/60001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:618: writer->WriteObjectImpl(Object::null(),
kAsInlinedObject);
Remove this one - this CL increases the number of fields written without
changing the number of fields read.

https://codereview.chromium.org/1323813004/diff/60001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:1638:
ContextScope::ZoneHandle(ContextScope::New(1, true));
ContextScope::New fails
Thread::Current()->no_safepoint_scope_depth() == 0
in a full snapshot