Enhance GN string interpolation.

Enhance GN string interpolation.

This allows writing scope accesses ${invoker.foo} and list accesses
${sources[0]} inside bracketed string interpolation.

Committed: https://crrev.com/f87ebd5381d93ab4540d66a525e6e1d058bd8f2b
Cr-Commit-Position: refs/heads/master@{#341547}

[brettw, 2015-08-03 00:24:48]

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

[commit-bot: I haz the power, 2015-08-03 00:24:57]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1268973003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1268973003/20001

[commit-bot: I haz the power, 2015-08-03 00:40:21]

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

[commit-bot: I haz the power, 2015-08-03 00:40:21]

Dry run: This issue passed the CQ dry run.

[brettw, 2015-08-03 04:47:49]

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

[Dirk Pranke, 2015-08-03 15:21:19]

lgtm

https://codereview.chromium.org/1268973003/diff/20001/tools/gn/string_utils.cc
File tools/gn/string_utils.cc (right):

https://codereview.chromium.org/1268973003/diff/20001/tools/gn/string_utils.c...
tools/gn/string_utils.cc:45: // non-general-purpose programming langhage. The
main reason expressions are
typo: "language".

https://codereview.chromium.org/1268973003/diff/20001/tools/gn/string_utils.c...
tools/gn/string_utils.cc:49: // In this simplified approach, we search for the
termianting '}' and execute
typo: "terminating".

[brettw, 2015-08-03 17:41:41]

The CQ bit was checked by brettw@chromium.org

[brettw, 2015-08-03 17:41:41]

The patchset sent to the CQ was uploaded after l-g-t-m from dpranke@chromium.org
Link to the patchset: https://codereview.chromium.org/1268973003/#ps40001
(title: " ")

[commit-bot: I haz the power, 2015-08-03 17:42:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1268973003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1268973003/40001

[commit-bot: I haz the power, 2015-08-03 18:01:33]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-08-03 18:02:53]

Patchset 3 (id:??) landed as
https://crrev.com/f87ebd5381d93ab4540d66a525e6e1d058bd8f2b
Cr-Commit-Position: refs/heads/master@{#341547}