[Android] Add gyp support for multidex.

build/android/gyp/dex.py

Index: build/android/gyp/dex.py
diff --git a/build/android/gyp/dex.py b/build/android/gyp/dex.py
index c26d23a61166627dba6c0acddd189301dd35c18a..3b4141f2f1418a47ff345d496ee54aaf86ae7674 100755
--- a/build/android/gyp/dex.py
+++ b/build/android/gyp/dex.py
@@ -4,21 +4,57 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import logging
 import optparse
 import os
 import sys
+import tempfile
+import zipfile
 
 from util import build_utils
 from util import md5_check
 
 
-def DoDex(options, paths):
+def DoMultiDex(options, paths):
+  main_dex_list = []
+  main_dex_list_files = build_utils.ParseGypList(options.main_dex_list_paths)
+  for m in main_dex_list_files:
+    with open(m) as main_dex_list_file:
+      main_dex_list.extend(l for l in main_dex_list_file if l)
+
+  with tempfile.NamedTemporaryFile(suffix='.txt') as combined_main_dex_list:
+    combined_main_dex_list.write('\n'.join(main_dex_list))
+    combined_main_dex_list.flush()
+
+    dex_args = [
+      '--multi-dex',
+      '--minimal-main-dex',
+      '--main-dex-list=%s' % combined_main_dex_list.name
+    ]
+
+    DoDex(options, paths, dex_args=dex_args)
+
+  if options.dex_path.endswith('.zip'):
+    iz = zipfile.ZipFile(options.dex_path, 'r')
+    tmp_dex_path = '%s.tmp.zip' % options.dex_path
+    oz = zipfile.ZipFile(tmp_dex_path, 'w', zipfile.ZIP_DEFLATED)
+    for i in iz.namelist():
+      if i.endswith('.dex'):
+        oz.writestr(i, iz.read(i))
+    os.remove(options.dex_path)
+    os.rename(tmp_dex_path, options.dex_path)
+
+
+def DoDex(options, paths, dex_args=None):
   dx_binary = os.path.join(options.android_sdk_tools, 'dx')
   # See http://crbug.com/272064 for context on --force-jumbo.
   dex_cmd = [dx_binary, '--dex', '--force-jumbo', '--output', options.dex_path]
   if options.no_locals != '0':
     dex_cmd.append('--no-locals')
 
+  if dex_args:
+    dex_cmd += dex_args
+
   dex_cmd += paths
 
   record_path = '%s.md5.stamp' % options.dex_path
@@ -54,9 +90,14 @@ def main():
                           'is enabled.'))
   parser.add_option('--no-locals',
                     help='Exclude locals list from the dex file.')
+  parser.add_option('--multi-dex', default=False, action='store_true',
+                    help='Create multiple dex files.')
   parser.add_option('--inputs', help='A list of additional input paths.')
   parser.add_option('--excluded-paths',
                     help='A list of paths to exclude from the dex file.')
+  parser.add_option('--main-dex-list-paths',
+                    help='A list of paths containing a list of the classes to '
+                         'include in the main dex.')
 
   options, paths = parser.parse_args(args)
 
@@ -76,7 +117,14 @@ def main():
     paths = [p for p in paths if not
              os.path.relpath(p, options.output_directory) in exclude_paths]
 
-  DoDex(options, paths)
+  if options.multi_dex and options.main_dex_list_paths:
+    DoMultiDex(options, paths)
+  else:
+    if options.multi_dex:
+      logging.warning('--multi-dex is unused without --main-dex-list-paths')
+    elif options.main_dex_list_paths:
+      logging.warning('--main-dex-list-paths is unused without --multi-dex')
+    DoDex(options, paths)
 
   if options.depfile:
     build_utils.WriteDepfile(