Move VR test APK downloading behind an env var

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 757 matching lines @@
   {
     'name': 'xstream',
     'pattern': '.',
     'action': ['python',
                'src/build/android/update_deps/update_third_party_deps.py',
                'download',
                '-b', 'chromium-robolectric',
                '-l', 'third_party/xstream'
     ],
   },
-  # Downloads the VR Services and Daydream Home APKs used for VR testing on
-  # Android.
-  {
-    'name': 'vr_services_apks',
-    'pattern': '.',
-    'action': ['python',
-               'src/build/android/update_deps/update_third_party_deps.py',
-               'download',
-               '-b', 'chrome-vr-test-apks/vr_services',
-               '-l', 'third_party/gvr-android-sdk/test-apks/vr_services'
-    ],
-  },
-  {
-    'name': 'daydream_home_apks',
-    'pattern': '.',
-    'action': ['python',
-               'src/build/android/update_deps/update_third_party_deps.py',
-               'download',
-               '-b', 'chrome-vr-test-apks/daydream_home',
-               '-l', 'third_party/gvr-android-sdk/test-apks/daydream_home'
-    ],
-  },
   {
     # Downloads the current stable linux sysroot to build/linux/ if needed.
     # This sysroot updates at about the same rate that the chrome build deps
     # change. This script is a no-op except for linux users who are doing
     # official chrome builds or cross compiling.
     'name': 'sysroot',
     'pattern': '.',
     'action': ['python', 'src/build/linux/sysroot_scripts/install-sysroot.py',
                '--running-as-hook'],
   },
@@ skipping 331 matching lines @@
     'name': 'webui_node_modules',
     'pattern': '.',
     'action': [ 'download_from_google_storage',
                 '--no_resume',
                 '--extract',
                 '--no_auth',
                 '--bucket', 'chromium-nodejs',
                 '-s', 'src/third_party/node/node_modules.tar.gz.sha1',
     ],
   },
+  # Download VR test APKs only if the environment variable is set
+  {
+    'name': 'vr_test_apks',
+    'pattern': '.',
+    'action': [ 'python',
+               'src/third_party/gvr-android-sdk/test-apks/update.py',
+    ],
+  },
 ]
 
 recursedeps = [
   # buildtools provides clang_format, libc++, and libc++abi
   'src/buildtools',
   # android_tools manages the NDK.
   'src/third_party/android_tools',
   # ANGLE manages DEPS that it also owns the build files for, such as dEQP.
   ("src/third_party/angle", "DEPS.chromium"),
   # SwiftShader manages DEPS that it also owns the build files for, such as Subzero.
   ("src/third_party/swiftshader", "DEPS"),
 ]