Add tools to build Dart with Chromium's sysroot.

Add tools to build Dart with Chromium's sysroot.

This downloads and uses the Debian Wheezy sysroot used by chromium,
when building Dart.  The resulting dart runtime requires libc version
2.14, and building without the sysroot requires libc version 2.16

BUG=https://github.com/dart-lang/sdk/issues/27048
R=sgjesse@google.com

Committed: https://github.com/dart-lang/sdk/commit/ae7b38799c386edbed3e1dcd4b6414087c6f49e6

[Søren Gjesse, 2016-08-10 13:44:01]

lgtm

Please update the wiki with information on this.

Also maybe buildbot scripts should have information that reproduction might need
to use the sysroot to get the same build.

https://codereview.chromium.org/2230083005/diff/1/tools/download_chromium_sys...
File tools/download_chromium_sysroot.sh (right):

https://codereview.chromium.org/2230083005/diff/1/tools/download_chromium_sys...
tools/download_chromium_sysroot.sh:16: git clone
https://chromium.googlesource.com/chromium/src/build
Do we want to pin this at a specific Git hash, to make sure we will not be hit
by breaking changes?

[Bill Hesse, 2016-08-10 14:04:09]

Description was changed from

==========
Add tools to build Dart with Chromium's sysroot.

This downloads and uses the Debian Wheezy sysroot used by chromium,
when building Dart.  The resulting dart runtime requires libc version
2.14, and building without the sysroot requires libc version 2.16

BUG=https://github.com/dart-lang/sdk/issues/27048
R=sgjesse@google.com
==========

to

==========
Add tools to build Dart with Chromium's sysroot.

This downloads and uses the Debian Wheezy sysroot used by chromium,
when building Dart.  The resulting dart runtime requires libc version
2.14, and building without the sysroot requires libc version 2.16

BUG=https://github.com/dart-lang/sdk/issues/27048
R=sgjesse@google.com

Committed:
https://github.com/dart-lang/sdk/commit/ae7b38799c386edbed3e1dcd4b6414087c6f49e6
==========

[Bill Hesse, 2016-08-10 14:04:11]

Committed patchset #1 (id:1) manually as
ae7b38799c386edbed3e1dcd4b6414087c6f49e6 (presubmit successful).

[Bill Hesse, 2016-08-10 14:04:27]

https://codereview.chromium.org/2230083005/diff/1/tools/download_chromium_sys...
File tools/download_chromium_sysroot.sh (right):

https://codereview.chromium.org/2230083005/diff/1/tools/download_chromium_sys...
tools/download_chromium_sysroot.sh:16: git clone
https://chromium.googlesource.com/chromium/src/build
On 2016/08/10 13:44:00, Søren Gjesse wrote:
> Do we want to pin this at a specific Git hash, to make sure we will not be hit
> by breaking changes?

I don't think so.  I think we should expect changes to happen rarely, and adapt
to them when they happen.  This script should mainly be run by hand anyway - I
don't plan to run it on the buildbots automatically.