Roll src/buildtools 9a90d9a..2dff9c9 (1 commit)

https://chromium.googlesource.com/chromium/buildtools/+log/9a90d9a..2dff9c9

This rolls GN from "UNKNOWN" to 1413 (4cf8d15..e134e49, 33 commits):

  https://gn.googlesource.com/gn/+log/4cf8d15..e134e49

  $ git log 4cf8d15..e134e49 --date=short --no-merges --format='%h %ad %s'

  e134e493 2018-08-13 Support specifying target and host platform in gen.py
  dd6a3831 2018-08-13 Switch to libc++ on Linux
  c218b836 2018-07-02 Don't use -- in exec_script
  27ef6b4e 2018-08-13 Fix gn_unittests
  f8f395ac 2018-08-10 Remove sarcastic error message.
  f9dbfd12 2018-08-10 Avoid trailing slashes for directory in compilation database
  c0744edf 2018-08-04 Add string_replace builtin function
  09171294 2018-07-31 [output_conversion] Add output_conversion options
  c2717deb 2018-08-02 [compdb] Properly escape for JSON
  f4facf42 2018-08-04 Don't allow ./ before target name.
  499868c6 2018-07-18 port gn to aix
  387e3ab4 2018-07-23 Add an OWNERS file.
  11e09914 2018-07-31 [docs] Updating documentation for compdb
  e2a2940a 2018-07-31 [target] Propagate configs across toolchains when specified
  d2d7ecb2 2018-07-30 Default to "ar" instead of "llvm-ar"
  9ae36b8b 2018-06-13 Update AUTHORS to reflect Chromium-tree contributions
  9a9ed6df 2018-07-26 Move all docs to toplevel docs/ folder.
  cad6b537 2018-07-23 Add notes about the CLA and gn-dev@ to the README.
  5d9a4e9a 2018-07-20 Make ICF an option in gen.py
  d7111cb6 2018-07-16 Enable identical code folding link option
  a6c2a5d5 2018-07-15 Use -ffunction-sections and -fdata-sections
  796ed47b 2018-07-16 Add reference.md
  63b72701 2018-07-15 Make LTO an option in gen.py
  d9bca564 2018-07-13 Fixes for --out-path and --no-sysroot
  0e4f3935 2018-07-13 Add options necessary for Chromium's bootstrap.py to forward to gen.py
  6ef28560 2018-07-13 Correct grammar in current_{cpu,os} docs
  8ce4e49a 2018-07-02 [gn] Add --export-compile-commands switch to gen
  f0b4405f 2018-07-09 Don't pass -flto.
  9911c782 2018-07-03 [command_args] Properly set file and line in dict
  39687ba9 2018-07-03 [command_args] Strip the preceding whitespace in comments if not padding
  fdc7a748 2018-06-29 Improve --version per discussion
  9cd5057b 2018-06-29 [recipes] Add --tags to git fetch command
  3ddcf64a 2018-06-29 Make gn --version work

TBR=fjhenigman@chromium.org

Change-Id: I54ae8b0c6d64174ec27e8eae7870eaa67d1dc037
Reviewed-on: https://chromium-review.googlesource.com/1173727
Commit-Queue: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583411}

DEPS

@@ -121,7 +121,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling build tools
   # and whatever else without interference from each other.
-  'buildtools_revision': '9a90d9aaadeb5e04327ed05775f45132e4b3523f',
+  'buildtools_revision': '2dff9c9c74e9d732e6fe57c84ef7fd044cc45d96',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.