[infra] Roll clang to match the version used by Flutter

DEPS

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 vars = {
   # The dart_root is the root of our sdk checkout. This is normally
   # simply sdk, but if using special gclient specs it can be different.
   "dart_root": "sdk",
 
   # We use mirrors of all github repos to guarantee reproducibility and
   # consistency between what users see and what the bots see.
   # We need the mirrors to not have 100+ bots pulling github constantly.
   # We mirror our github repos on chromium git servers.
   # DO NOT use this var if you don't see a mirror here:
   #   https://chromium.googlesource.com/
   # named like:
   #   external/github.com/dart-lang/NAME
   # It is ok to add a dependency directly on dart-lang (dart-lang only)
   # github repo until the mirror has been created, but please do file a bug
   # against infra to make that happen.
   "github_mirror":
       "https://chromium.googlesource.com/external/github.com/dart-lang/%s.git",
 
   # Chromium git
   "chromium_git": "https://chromium.googlesource.com",
+  "fuchsia_git": "https://fuchsia.googlesource.com",
 
   # Only use this temporarily while waiting for a mirror for a new package.
   "github_dartlang": "https://github.com/dart-lang/%s.git",
 
   "gyp_rev": "@6ee91ad8659871916f9aa840d42e1513befdf638",
   "co19_rev": "@4af9ef149be554216c5bb16cbac8e50d4c28cdf1",
 
-  # Revisions of GN related dependencies.
-  "buildtools_revision": "@39b1db2ab4aa4b2ccaa263c29bdf63e7c1ee28aa",
-  "clang_format_rev": "@0ed791d1387a3c9146ea6c453c646f3c0fc97784",
+  # Revisions of GN related dependencies. This should match the revision
+  # pulled by Flutter.
+  "buildtools_revision": "@c8db819853bcf8ce1635a8b7a395820f39b5a9fc",
+
+  # Scripts that make 'git cl format' work.
+  "clang_format_scripts_rev": "@c09c8deeac31f05bd801995c475e7c8070f9ecda",
 
   "gperftools_revision": "@02eeed29df112728564a5dde6417fa4622b57a06",
 
   # Revisions of /third_party/* dependencies.
   "args_tag": "@0.13.7",
   "async_tag": "@1.13.0",
   "barback-0.13.0_rev": "@34853",
   "barback-0.14.0_rev": "@36398",
   "barback-0.14.1_rev": "@38525",
   "barback_tag" : "@0.15.2+9",
@@ skipping 79 matching lines @@
   "zlib_rev": "@c3d0a6190f2f8c924a05ab6cc97b8f975bddd33f",
 }
 
 deps = {
   # Stuff needed for GYP to run.
   Var("dart_root") + "/third_party/gyp":
       Var('chromium_git') + '/external/gyp.git' + Var("gyp_rev"),
 
   # Stuff needed for GN build.
   Var("dart_root") + "/buildtools":
-     Var('chromium_git') + '/chromium/buildtools.git' +
-     Var('buildtools_revision'),
+     Var("fuchsia_git") + "/buildtools" + Var("buildtools_revision"),
   Var("dart_root") + "/buildtools/clang_format/script":
     Var("chromium_git") + "/chromium/llvm-project/cfe/tools/clang-format.git" +
-    Var("clang_format_rev"),
+    Var("clang_format_scripts_rev"),
 
   Var("dart_root") + "/tests/co19/src":
       (Var("github_mirror") % "co19") + Var("co19_rev"),
 
   Var("dart_root") + "/third_party/zlib":
       Var("chromium_git") + "/chromium/src/third_party/zlib.git" +
       Var("zlib_rev"),
 
   Var("dart_root") + "/third_party/boringssl":
       (Var("github_mirror") % "boringssl_gen") + Var("boringssl_gen_rev"),
@@ skipping 189 matching lines @@
       Var("web_socket_channel_tag"),
   Var("dart_root") + "/third_party/pkg/when":
       (Var("github_mirror") % "when") + Var("when_tag"),
   Var("dart_root") + "/third_party/pkg/which":
       (Var("github_mirror") % "which") + Var("which_tag"),
   Var("dart_root") + "/third_party/pkg/yaml":
       (Var("github_mirror") % "yaml") + Var("yaml_tag"),
 }
 
 deps_os = {
-  "android": {
-    Var("dart_root") + "/third_party/android_tools":
-      Var("chromium_git") + "/android_tools.git" +
-      "@aaeda3d69df4b4352e3cac7c16bea7f16bd1ec12",
-  },
   "win": {
     Var("dart_root") + "/third_party/cygwin":
       Var("chromium_git") + "/chromium/deps/cygwin.git" +
       "@c89e446b273697fadf3a10ff1007a97c0b7de6df",
   },
 }
 
 # TODO(iposva): Move the necessary tools so that hooks can be run
 # without the runtime being available.
 hooks = [
-  # Pull GN binaries. This needs to be before running GYP below.
-  {
-    'name': 'gn_linux64',
-    'pattern': '.',
-    'action': [
-      'download_from_google_storage',

[Bill Hesse, 2017/05/03 16:05:34]

Is GN now downloaded by the clang or buildtools actions?

[Bill Hesse, 2017/05/03 16:06:47]

Yes it is.

-      '--no_auth',
-      '--no_resume',
-      '--quiet',
-      '--platform=linux*',
-      '--bucket',
-      'chromium-gn',
-      '-s',
-      Var('dart_root') + '/buildtools/linux64/gn.sha1',
-    ],
-  },
-  {
-    'name': 'gn_mac',
-    'pattern': '.',
-    'action': [
-      'download_from_google_storage',
-      '--no_auth',
-      '--no_resume',
-      '--quiet',
-      '--platform=darwin',
-      '--bucket',
-      'chromium-gn',
-      '-s',
-      Var('dart_root') + '/buildtools/mac/gn.sha1',
-    ],
-  },
-  {
-    'name': 'gn_win',
-    'pattern': '.',
-    'action': [
-      'download_from_google_storage',
-      '--no_auth',
-      '--no_resume',
-      '--quiet',
-      '--platform=win*',
-      '--bucket',
-      'chromium-gn',
-      '-s',
-      Var('dart_root') + '/buildtools/win/gn.exe.sha1',
-    ],
-  },
-  # Pull clang-format binaries using checked-in hashes.
-  {
-    'name': 'clang_format_win',
-    'pattern': '.',
-    'action': [
-      'download_from_google_storage',
-      '--no_auth',
-      '--no_resume',
-      '--quiet',
-      '--platform=win32',
-      '--bucket',
-      'chromium-clang-format',
-      '-s',
-      Var('dart_root') + '/buildtools/win/clang-format.exe.sha1',
-    ],
-  },
-  {
-    'name': 'clang_format_linux',
-    'pattern': '.',
-    'action': [
-      'download_from_google_storage',
-      '--no_auth',
-      '--no_resume',
-      '--quiet',
-      '--platform=linux*',
-      '--bucket',
-      'chromium-clang-format',
-      '-s',
-      Var('dart_root') + '/buildtools/linux64/clang-format.sha1',
-    ],
-  },
-  {
-    'name': 'clang_format_mac',
-    'pattern': '.',
-    'action': [
-      'download_from_google_storage',
-      '--no_auth',
-      '--no_resume',
-      '--quiet',
-      '--platform=darwin',
-      '--bucket',
-      'chromium-clang-format',
-      '-s',
-      Var('dart_root') + '/buildtools/mac/clang-format.sha1',
-    ],
-  },
   {
     'name': 'd8_testing_binaries',
     'pattern': '.',
     'action': [
       'download_from_google_storage',
       '--no_auth',
       '--no_resume',
       '--bucket',
       'dart-dependencies',
       '--recursive',
@@ skipping 86 matching lines @@
       "--no_auth",
       "--no_resume",
       "--bucket",
       "dart-dependencies",
       "--extract",
       "-s",
       Var('dart_root') + "/third_party/gsutil.tar.gz.sha1",
     ],
   },
   {
-    "name": "clang",
-    "pattern": ".",
-    "action": [
-      "download_from_google_storage",
-      "--no_auth",
-      "--no_resume",
-      "--bucket",
-      "dart-dependencies",
-      "--platform=linux*",
-      "--extract",
-      "-s",
-      Var('dart_root') + "/third_party/clang.tar.gz.sha1",
-    ],
-  },
-  {
     # Pull Debian wheezy sysroot for i386 Linux
     'name': 'sysroot_i386',
     'pattern': '.',
     'action': ['python', 'sdk/build/linux/sysroot_scripts/install-sysroot.py',
                '--running-as-hook', '--arch', 'i386'],
   },
   {
     # Pull Debian wheezy sysroot for amd64 Linux
     'name': 'sysroot_amd64',
     'pattern': '.',
     'action': ['python', 'sdk/build/linux/sysroot_scripts/install-sysroot.py',
                '--running-as-hook', '--arch', 'amd64'],
   },
   {
-    # Pull clang if needed or requested via GYP_DEFINES.
-    'name': 'gn_clang',
+    'name': 'download_android_tools',
     'pattern': '.',
-    'action': ['python', 'sdk/tools/clang/scripts/update.py', '--if-needed'],
+    'action': ['python', 'sdk/tools/android/download_android_tools.py'],

[Bill Hesse, 2017/05/03 16:05:34]

Is this going to pull down all the NDK and SDK and more in every checkout? 
Before this only happened if OS=android was added at the end of the gclient
file.

If so, explain the tradeoffs and benefits.

[Bill Hesse, 2017/05/03 16:06:47]

It only downloads a trimmed set, so OK.

[zra, 2017/05/03 17:34:41]

Improvements:
- Downloads of a stripped-down blob instead of cloning a big git repo.
- Same version that Flutter uses.
- Don't need to edit the .gclient file to grab it.

Possible downsides:
- Pulled even for folks not work on Android issues.
  - However, download is only one-time, and now also works for Mac, so makes
more sense to pull it by default.

+  },
+  {
+    'name': 'buildtools',
+    'pattern': '.',
+    'action': ['python', 'sdk/tools/buildtools/update.py'],
   },
   {
     # Update the Windows toolchain if necessary.
     'name': 'win_toolchain',
     'pattern': '.',
     'action': ['python', 'sdk/build/vs_toolchain.py', 'update'],
   },
   {
     "pattern": ".",
     "action": ["python", Var("dart_root") + "/tools/generate_buildfiles.py"],
   },
 ]