message: Rename some variables and functions in AndroidKeystoreAesGcm.
  These names match what we use elsewhere.
diff: @@ -63,18 +63,18 @@ public final class AndroidKeystoreAesGcm implements Aead {
  }
  @Override
  - public byte[] encrypt(final byte[] plaintext, final byte[] aad)
  + public byte[] encrypt(final byte[] plaintext, final byte[] associatedData)
  throws GeneralSecurityException {
  try {
  - return encryptInternal(plaintext, aad);
  + return encryptInternal(plaintext, associatedData);
  } catch (ProviderException | GeneralSecurityException ex) {
  Log.w(TAG, "encountered a potentially transient KeyStore error, will wait and retry", ex);
  - sleep();
  - return encryptInternal(plaintext, aad);
  + sleepRandomAmount();
  + return encryptInternal(plaintext, associatedData);
  }
  }
  - private byte[] encryptInternal(final byte[] plaintext, final byte[] aad)
  + private byte[] encryptInternal(final byte[] plaintext, final byte[] associatedData)
  throws GeneralSecurityException {
  // Check that ciphertext is not longer than the max. size of a Java array.
  if (plaintext.length > Integer.MAX_VALUE - IV_SIZE_IN_BYTES - TAG_SIZE_IN_BYTES) {
  @@ -83,7 +83,7 @@ public final class AndroidKeystoreAesGcm implements Aead {
  byte[] ciphertext = new byte[IV_SIZE_IN_BYTES + plaintext.length + TAG_SIZE_IN_BYTES];
  Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
  cipher.init(Cipher.ENCRYPT_MODE, key);
  - cipher.updateAAD(aad);
  + cipher.updateAAD(associatedData);
  int unusedWritten =
  cipher.doFinal(plaintext, 0, plaintext.length, ciphertext, IV_SIZE_IN_BYTES);
  // Copy the IV that is randomly generated by Android Keystore.
  @@ -92,32 +92,33 @@ public final class AndroidKeystoreAesGcm implements Aead {
  }
  @Override
  - public byte[] decrypt(final byte[] ciphertext, final byte[] aad) throws GeneralSecurityException {
  + public byte[] decrypt(final byte[] ciphertext, final byte[] associatedData)
  + throws GeneralSecurityException {
  if (ciphertext.length < IV_SIZE_IN_BYTES + TAG_SIZE_IN_BYTES) {
  throw new GeneralSecurityException("ciphertext too short");
  }
  try {
  - return decryptInternal(ciphertext, aad);
  + return decryptInternal(ciphertext, associatedData);
  } catch (AEADBadTagException ex) {
  throw ex;
  } catch (ProviderException | GeneralSecurityException ex) {
  Log.w(TAG, "encountered a potentially transient KeyStore error, will wait and retry", ex);
  - sleep();
  - return decryptInternal(ciphertext, aad);
  + sleepRandomAmount();
  + return decryptInternal(ciphertext, associatedData);
  }
  }
  - private byte[] decryptInternal(final byte[] ciphertext, final byte[] aad)
  + private byte[] decryptInternal(final byte[] ciphertext, final byte[] associatedData)
  throws GeneralSecurityException {
  GCMParameterSpec params =
  new GCMParameterSpec(8 * TAG_SIZE_IN_BYTES, ciphertext, 0, IV_SIZE_IN_BYTES);
  Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
  cipher.init(Cipher.DECRYPT_MODE, key, params);
  - cipher.updateAAD(aad);
  + cipher.updateAAD(associatedData);
  return cipher.doFinal(ciphertext, IV_SIZE_IN_BYTES, ciphertext.length - IV_SIZE_IN_BYTES);
  }
  - private static void sleep() {
  + private static void sleepRandomAmount() {
  int waitTimeMillis = (int) (Math.random() * MAX_WAIT_TIME_MILLISECONDS_BEFORE_RETRY);
  try {
  Thread.sleep(waitTimeMillis);
  