Remove new space allocation in optimizing compiler, use Symbols::FromConcat where appropriate

Remove new space allocation in optimizing compiler, use Symbols::FromConcat where appropriate

BUG=
R=hausner@google.com

Committed: https://github.com/dart-lang/sdk/commit/428071665626f5f97e963179a6d01493cdfd3ac3

[srdjan, 2015-08-20 21:35:14]

srdjan@google.com changed reviewers:
+ hausner@google.com

[hausner, 2015-08-20 21:45:46]

lgtm

https://codereview.chromium.org/1303923002/diff/20001/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

https://codereview.chromium.org/1303923002/diff/20001/runtime/vm/parser.cc#ne...
runtime/vm/parser.cc:13044: String::Handle(Symbols::FromConcat(type_class_name,
Symbols::Dot()));
Isn't it premature to create a symbol here? If it's a named constructor, we
create and canonicalize a string that isn't going to be used.

[srdjan, 2015-08-20 22:11:18]

https://codereview.chromium.org/1303923002/diff/20001/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

https://codereview.chromium.org/1303923002/diff/20001/runtime/vm/parser.cc#ne...
runtime/vm/parser.cc:13044: String::Handle(Symbols::FromConcat(type_class_name,
Symbols::Dot()));
On 2015/08/20 21:45:46, hausner wrote:
> Isn't it premature to create a symbol here? If it's a named constructor, we
> create and canonicalize a string that isn't going to be used.

Discussed offline, agreed to keep it as it is, otherwise new strings would be
allocated repeatedly. We also need this in order to prevent allocation in new
space (optimizing compiler in helper thread)

[srdjan, 2015-08-20 22:14:05]

Committed patchset #2 (id:20001) manually as
428071665626f5f97e963179a6d01493cdfd3ac3 (presubmit successful).