[dart:io] Adds Platform.ansiSupported

[dart:io] Adds Platform.ansiSupported

This is so that flutter_tool can determine whether it can print
ANSI codes to the terminal on windows.

fixes #28614,#28984

R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/a8bf498e5698c67676da3ab942ed3b51e88181a7

[zra, 2017-03-10 22:50:01]

Description was changed from

==========
[dart:io] Adds Platform.ansiSupported

fixes #28614,#28984
==========

to

==========
[dart:io] Adds Platform.ansiSupported

This is so that flutter_tool can determine whether it can print
ANSI codes to the terminal on windows.

fixes #28614,#28984
==========

[zra, 2017-03-10 22:50:08]

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

[siva, 2017-03-10 23:39:03]

lgtm

https://codereview.chromium.org/2739683005/diff/1/runtime/bin/platform.cc
File runtime/bin/platform.cc (right):

https://codereview.chromium.org/2739683005/diff/1/runtime/bin/platform.cc#new...
runtime/bin/platform.cc:114: Dart_SetReturnValue(args,
Dart_NewBoolean(Platform::AnsiSupported()));
You could use
Dart_SetBooleanReturnValue(args, Platform::AnsiSupported());

[zra, 2017-03-15 15:51:55]

Description was changed from

==========
[dart:io] Adds Platform.ansiSupported

This is so that flutter_tool can determine whether it can print
ANSI codes to the terminal on windows.

fixes #28614,#28984
==========

to

==========
[dart:io] Adds Platform.ansiSupported

This is so that flutter_tool can determine whether it can print
ANSI codes to the terminal on windows.

fixes #28614,#28984

R=asiva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/a8bf498e5698c67676da3ab942ed3b51e88181a7
==========

[zra, 2017-03-15 15:51:56]

Committed patchset #5 (id:80001) manually as
a8bf498e5698c67676da3ab942ed3b51e88181a7 (presubmit successful).

[zra, 2017-03-15 17:03:57]

https://codereview.chromium.org/2739683005/diff/1/runtime/bin/platform.cc
File runtime/bin/platform.cc (right):

https://codereview.chromium.org/2739683005/diff/1/runtime/bin/platform.cc#new...
runtime/bin/platform.cc:114: Dart_SetReturnValue(args,
Dart_NewBoolean(Platform::AnsiSupported()));
On 2017/03/10 23:39:03, siva wrote:
> You could use
> Dart_SetBooleanReturnValue(args, Platform::AnsiSupported());
>  

Done.

[sortie, 2017-03-16 11:39:07]

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

[sortie, 2017-03-16 11:39:08]

https://codereview.chromium.org/2739683005/diff/80001/runtime/bin/platform_wi...
File runtime/bin/platform_win.cc (right):

https://codereview.chromium.org/2739683005/diff/80001/runtime/bin/platform_wi...
runtime/bin/platform_win.cc:89: ansi_supported_ = false;
This looks like escape codes are considered unsupported if the input is not a
terminal, but support for escape codes only has to do with the console output. I
could imagine redirecting a file as input or using a pipe into a dart program
and still expect color output. There is no support for STD_ERROR_HANDLE here
either. The terminalness of the standard output and standard error are in
principle distinct and Platform should probably expose a different bool for
whether each of those support escape sequences.