Roll buildtools b73e5f0d7ac..dc487f429cb9 to roll GN 329298:330790

Roll buildtools b73e5f0d7ac..dc487f429cb9 to roll GN 329298:330790.

List of changes:

https://chromium.googlesource.com/chromium/buildtools/+log/b73e5f70d7ac..dc487f429cb9

commit dc487f429cb90cac92ec7a9cd9d49db13648064d
Author: Dirk Pranke <dpranke@chromium.org>;
Date:   Wed May 20 14:44:08 2015 -0700

    Roll GN 329298:330790 (c947c40710fe..9d04333fe102)

    List of changes in tools/gn:

    https://chromium.googlesource.com/chromium/src/+log/c947c40710fe..9d04333fe102/tools/gn

    This roll mostly pulls in two new GN features:

    1) a new 'gn path' command for finding the dependencies
    linking two targets

    2) the 'runtime_deps' option to 'gn desc', which will compute
    the list of files needed to for a target to run based
    on the dependencies and data files listed on the targets. If
    --runtime-deps-list-file is specified when 'gn gen' is run,
    GN will also write out the dependencies for the targets listed
    in the file to $target.runtime_deps files.

    TBR=brettw@chromium.org
    BUG=480053
R=brettw@chromium.org
BUG=480053
CQ_EXTRA_TRYBOTS=tryserver.chromium.mac:mac_chromium_gn_rel;tryserver.chromium.win:win8_chromium_gn_rel

Committed: https://crrev.com/f89d9b09d549eeebd330b1117f06ed8a02486e8b
Cr-Commit-Position: refs/heads/master@{#330865}

[Dirk Pranke, 2015-05-20 21:51:35]

The CQ bit was checked by dpranke@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-05-20 21:52:08]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1148283002/20001

[commit-bot: I haz the power, 2015-05-20 23:33:00]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-05-20 23:33:01]

Dry run: This issue passed the CQ dry run.

[Dirk Pranke, 2015-05-21 00:48:25]

dpranke@chromium.org changed reviewers:
+ brettw@chromium.org

[brettw, 2015-05-21 00:49:15]

lgtm

[Dirk Pranke, 2015-05-21 00:49:40]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2015-05-21 00:50:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1148283002/20001

[commit-bot: I haz the power, 2015-05-21 00:55:43]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-21 00:56:32]

Patchset 2 (id:??) landed as
https://crrev.com/f89d9b09d549eeebd330b1117f06ed8a02486e8b
Cr-Commit-Position: refs/heads/master@{#330865}