[Swarming] Bundle gcmole tools.

This enables downloading all gcmole dependencies from
google storage on demand, controlled by a gyp flag
"gcmole=1". This makes the analysis portable to any linux64
host. The archive contains a prebuilt clang in the needed
version, the gcmole plugin and a lua binary.

The tool can be run through a new wrapper that sets up the
environment. This'll ease running it on swarming.

BUG=chromium:535160
LOG=n

Review URL: https://codereview.chromium.org/1703533002

Cr-Commit-Position: refs/heads/master@{#34046}

.gitignore

@@ -66,6 +66,8 @@ shell_g
 /third_party/llvm
 /third_party/llvm-build
 /tools/clang
+/tools/gcmole/gcmole-tools
+/tools/gcmole/gcmole-tools.tar.gz
 /tools/jsfunfuzz
 /tools/jsfunfuzz.zip
 /tools/luci-go/linux64/isolate

DEPS

@@ -102,6 +102,14 @@ hooks = [
                 "-s", "v8/buildtools/linux64/clang-format.sha1",
     ],
   },
+  {
+    'name': 'gcmole',
+    'pattern': '.',
+    'action': [
+        'python',
+        'v8/tools/gcmole/download_gcmole_tools.py',
+    ],
+  },
   # Pull luci-go binaries (isolate, swarming) using checked-in hashes.
   {
     'name': 'luci-go_win',

tools/gcmole/download_gcmole_tools.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import re
+import subprocess
+
+GCMOLE_PATH = os.path.dirname(os.path.abspath(__file__))
+SHA1_PATH = os.path.join(GCMOLE_PATH, 'gcmole-tools.tar.gz.sha1')
+
+if re.search(r'\bgcmole=1', os.environ.get('GYP_DEFINES', '')):
+  subprocess.check_call([
+    'download_from_google_storage',
+    '-b', 'chrome-v8-gcmole',
+    '-u', '--no_resume',
+    '-s', SHA1_PATH,
+    '--platform=linux*'
+  ])
+else:
+  print 'Skipping gcmole download as gcmole is not set in gyp flags.'

tools/gcmole/gcmole-tools.tar.gz.sha1

@@ -0,0 +1 @@
+b10748117f8f53d05dda0a77424b8794e645e330

tools/gcmole/run-gcmole.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import subprocess
+import sys
+
+GCMOLE_PATH = os.path.dirname(os.path.abspath(__file__))
+CLANG_BIN = os.path.join(GCMOLE_PATH, 'gcmole-tools', 'bin')
+CLANG_PLUGINS = os.path.join(GCMOLE_PATH, 'gcmole-tools')
+LUA = os.path.join(GCMOLE_PATH, 'gcmole-tools', 'lua52')
+DRIVER = os.path.join(GCMOLE_PATH, 'gcmole.lua')
+
+assert len(sys.argv) == 2
+
+sys.exit(subprocess.call(
+    [LUA, DRIVER, sys.argv[1]],
+    env={'CLANG_BIN': CLANG_BIN, 'CLANG_PLUGINS': CLANG_PLUGINS},
+))