Recognize and special case String.fromCharCodes for Uint8List in JavaScript.

Recognize and special case String.fromCharCodes for Uint8List in JavaScript.

Speeds up UTF8 decoding, boosting JsonUtf8RoundTrip 4x.
This should also improve binary protobuf parsing of strings.

R=lrn@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43055

[sra1, 2015-01-21 06:19:14]

sra@google.com changed reviewers:
+ lrn@google.com

[Lasse Reichstein Nielsen, 2015-01-21 09:36:38]

lgtm

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
File sdk/lib/_internal/compiler/js_lib/core_patch.dart (right):

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
sdk/lib/_internal/compiler/js_lib/core_patch.dart:17: import 'dart:typed_data'
show Uint8List;
Is this import used?

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
sdk/lib/_internal/compiler/js_lib/core_patch.dart:314: int end =
_checkBounds(len, start, endOrNull);
You should soon be able to use RangeError.checkValidRange(start, endOrNull, len)
instead, when I commit any of the CLs I have that make it return the length.

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
File sdk/lib/_internal/compiler/js_lib/js_helper.dart (right):

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
sdk/lib/_internal/compiler/js_lib/js_helper.dart:776: int chunkEnd = i +
kMaxApply < end ? i + kMaxApply : end;
Parentheses around ?-condition if it's non-trivial.

[sra1, 2015-01-21 20:27:06]

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
File sdk/lib/_internal/compiler/js_lib/core_patch.dart (right):

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
sdk/lib/_internal/compiler/js_lib/core_patch.dart:17: import 'dart:typed_data'
show Uint8List;
On 2015/01/21 09:36:38, Lasse Reichstein Nielsen wrote:
> Is this import used?

Done.

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
File sdk/lib/_internal/compiler/js_lib/js_helper.dart (right):

https://codereview.chromium.org/860273002/diff/1/sdk/lib/_internal/compiler/j...
sdk/lib/_internal/compiler/js_lib/js_helper.dart:776: int chunkEnd = i +
kMaxApply < end ? i + kMaxApply : end;
On 2015/01/21 09:36:38, Lasse Reichstein Nielsen wrote:
> Parentheses around ?-condition if it's non-trivial.

Done.

[sra1, 2015-01-21 22:50:08]

Committed patchset #2 (id:20001) manually as 43055 (presubmit successful).