Add hook for sdkextras, clean out stale entries

DEPS

 # This file is automatically processed to create .DEPS.git which is the file
 # that gclient uses under git.
 #
 # See http://code.google.com/p/chromium/wiki/UsingGit
 #
 # To test manually, run:
 #   python tools/deps2git/deps2git.py -o .DEPS.git -w <gclientdir>
 # where <gcliendir> is the absolute path to the directory containing the
 # .gclient file (the parent of 'src').
 #
@@ skipping 201 matching lines @@
     # first hook so that other things that get/generate into the output
     # directory will not subsequently be clobbered.
     'name': 'landmines',
     'pattern': '.',
     'action': [
         'python',
         'src/build/landmines.py',
     ],
   },
   {
-    # Downloads an ARM sysroot image to src/arm-sysroot. This image updates
-    # at about the same rate that the chrome build deps change.
-    # This script is a no-op except for linux users who have
-    # target_arch=arm in their GYP_DEFINES.
-    'name': 'sysroot',
-    'pattern': '.',
-    'action': ['python', 'src/build/linux/install-arm-sysroot.py',
-               '--linux-only'],
-  },
-  {
     # Pull clang if needed or requested via GYP_DEFINES.
     'name': 'clang',
     'pattern': '.',
     'action': ['python', 'src/tools/clang/scripts/update.py', '--if-needed'],
   },
   {
     # Pull dart sdk if needed
     'name': 'dart',
     'pattern': '.',
     'action': ['python', 'src/tools/dart/update.py'],
   },
   {
-    # Update the Windows toolchain if necessary.
-    'name': 'win_toolchain',
+    # This downloads SDK extras and puts them in the
+    # third_party/android_tools/sdk/extras directory on the bots. Developers
+    # need to manually install these packages and accept the ToS.
+    'name': 'sdkextras',
     'pattern': '.',
-    'action': ['python', 'src/build/vs_toolchain.py', 'update'],
+    # When adding a new sdk extras package to download, add the package
+    # directory and zip file to .gitignore in third_party/android_tools.
+    'action': ['python', 'src/build/download_sdk_extras.py'],
   },
   {
     # Update LASTCHANGE. This is also run by export_tarball.py in
     # src/tools/export_tarball - please keep them in sync.
     'name': 'lastchange',
     'pattern': '.',
     'action': ['python', 'src/build/util/lastchange.py',
                '-o', 'src/build/util/LASTCHANGE'],
   },
   # Pull GN binaries. This needs to be before running GYP below.
@@ skipping 80 matching lines @@
     # corresponding .py files have already been deleted.
     'name': 'remove_stale_pyc_files',
     'pattern': 'src/tools/.*\\.py',
     'action': [
         'python',
         'src/tools/remove_stale_pyc_files.py',
         'src/tools',
     ],
   },
 ]