[Android] grant READ_EXTERNAL_STORAGE permission when adding WRITE_EXTERNAL_STORAGE.

build/android/devil/android/device_utils.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Provides a variety of device interactions based on adb.
 
 Eventually, this will be based on adb_wrapper.
 """
 # pylint: disable=unused-argument
 
@@ skipping 547 matching lines @@
       # We won't know the resulting device apk names.
       self._cache['package_apk_paths'].pop(package_name, 0)
       self.adb.Install(apk_path, reinstall=reinstall)
       self._cache['package_apk_checksums'][package_name] = host_checksums
 
     if (permissions is None
         and self.build_version_sdk >= version_codes.MARSHMALLOW):
       permissions = apk_helper.ApkHelper(apk_path).GetPermissions()
     self.GrantPermissions(package_name, permissions)
 
-
   @decorators.WithTimeoutAndRetriesDefaults(
       INSTALL_DEFAULT_TIMEOUT,
       INSTALL_DEFAULT_RETRIES)
   def InstallSplitApk(self, base_apk, split_apks, reinstall=False,
                       allow_cached_props=False, timeout=None, retries=None):
     """Install a split APK.
 
     Noop if all of the APK splits are already installed.
 
     Args:
@@ skipping 1377 matching lines @@
 
   @decorators.WithTimeoutAndRetriesFromInstance()
   def GrantPermissions(self, package, permissions, timeout=None, retries=None):
     # Permissions only need to be set on M and above because of the changes to
     # the permission model.
     if not permissions or self.build_version_sdk < version_codes.MARSHMALLOW:
       return
     # TODO(rnephew): After permission blacklist is complete, switch to using
     # &&s instead of ;s.
     cmd = ''
-    logging.info('Setting permissions for %s', package)
-    for p in permissions:
-      if p not in _PERMISSIONS_BLACKLIST:
-        cmd += 'pm grant %s %s;' % (package, p)
-        logging.info('  %s', p)
+    logging.info('Setting permissions for %s.', package)
+    permissions = [p for p in permissions if p not in _PERMISSIONS_BLACKLIST]
+    if ('android.permission.WRITE_EXTERNAL_STORAGE' in permissions
+        and 'android.permission.READ_EXTERNAL_STORAGE' not in permissions):
+      permissions.append('android.permission.READ_EXTERNAL_STORAGE')
+    cmd = ';'.join('pm grant %s %s' %(package, p) for p in permissions)
     if cmd:
       output = self.RunShellCommand(cmd)
       if output:
         logging.warning('Possible problem when granting permissions. Blacklist '
                         'may need to be updated.')
         logging.warning(output)