Give "PhabricatorUserEmail" a PHID

Summary:
Ref T13444. To interact meaningfully with "DestructionEngine", objects need a PHID. The "UserEmail" object currently does not have one (or a real "Query").

Provide basic PHID support so "DestructionEngine" can interact with the object more powerfully.

Test Plan:
- Ran migrations, checked data in database, saw sensible PHIDs assigned.
- Added a new email address to my account, saw it get a PHID.

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T13444

Differential Revision: https://secure.phabricator.com/D20913

resources/sql/autopatches/20191114.email.01.phid.sql

···
+ALTER TABLE {$NAMESPACE}_user.user_email
+  ADD phid VARBINARY(64) NOT NULL;

resources/sql/autopatches/20191114.email.02.populate.php

···
+<?php
+
+$table = new PhabricatorUserEmail();
+$conn = $table->establishConnection('w');
+
+$iterator = new LiskRawMigrationIterator($conn, $table->getTableName());
+foreach ($iterator as $row) {
+  $phid = $row['phid'];
+
+  if (!strlen($phid)) {
+    queryfx(
+      $conn,
+      'UPDATE %R SET phid = %s WHERE id = %d',
+      $table,
+      $table->generatePHID(),
+      $row['id']);
+  }
+}

src/__phutil_library_map__.php

···
     'PhabricatorPeopleTasksProfileMenuItem' => 'applications/people/menuitem/PhabricatorPeopleTasksProfileMenuItem.php',
     'PhabricatorPeopleTestDataGenerator' => 'applications/people/lipsum/PhabricatorPeopleTestDataGenerator.php',
     'PhabricatorPeopleTransactionQuery' => 'applications/people/query/PhabricatorPeopleTransactionQuery.php',
+    'PhabricatorPeopleUserEmailPHIDType' => 'applications/people/phid/PhabricatorPeopleUserEmailPHIDType.php',
+    'PhabricatorPeopleUserEmailQuery' => 'applications/people/query/PhabricatorPeopleUserEmailQuery.php',
     'PhabricatorPeopleUserFunctionDatasource' => 'applications/people/typeahead/PhabricatorPeopleUserFunctionDatasource.php',
     'PhabricatorPeopleUserPHIDType' => 'applications/people/phid/PhabricatorPeopleUserPHIDType.php',
     'PhabricatorPeopleUsernameMailEngine' => 'applications/people/mail/PhabricatorPeopleUsernameMailEngine.php',
···
     'PhabricatorPeopleTasksProfileMenuItem' => 'PhabricatorProfileMenuItem',
     'PhabricatorPeopleTestDataGenerator' => 'PhabricatorTestDataGenerator',
     'PhabricatorPeopleTransactionQuery' => 'PhabricatorApplicationTransactionQuery',
+    'PhabricatorPeopleUserEmailPHIDType' => 'PhabricatorPHIDType',
+    'PhabricatorPeopleUserEmailQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'PhabricatorPeopleUserFunctionDatasource' => 'PhabricatorTypeaheadCompositeDatasource',
     'PhabricatorPeopleUserPHIDType' => 'PhabricatorPHIDType',
     'PhabricatorPeopleUsernameMailEngine' => 'PhabricatorPeopleMailEngine',

src/applications/people/phid/PhabricatorPeopleUserEmailPHIDType.php

···
+<?php
+
+final class PhabricatorPeopleUserEmailPHIDType
+  extends PhabricatorPHIDType {
+
+  const TYPECONST = 'EADR';
+
+  public function getTypeName() {
+    return pht('User Email');
+  }
+
+  public function newObject() {
+    return new PhabricatorUserEmail();
+  }
+
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorPeopleApplication';
+  }
+
+  protected function buildQueryForObjects(
+    PhabricatorObjectQuery $query,
+    array $phids) {
+
+    return id(new PhabricatorPeopleUserEmailQuery())
+      ->withPHIDs($phids);
+  }
+
+  public function loadHandles(
+    PhabricatorHandleQuery $query,
+    array $handles,
+    array $objects) {
+    return null;
+  }
+
+}

src/applications/people/query/PhabricatorPeopleUserEmailQuery.php

···
+<?php
+
+final class PhabricatorPeopleUserEmailQuery
+  extends PhabricatorCursorPagedPolicyAwareQuery {
+
+  private $ids;
+  private $phids;
+
+  public function withIDs(array $ids) {
+    $this->ids = $ids;
+    return $this;
+  }
+
+  public function withPHIDs(array $phids) {
+    $this->phids = $phids;
+    return $this;
+  }
+
+  public function newResultObject() {
+    return new PhabricatorUserEmail();
+  }
+
+  protected function loadPage() {
+    return $this->loadStandardPage($this->newResultObject());
+  }
+
+  protected function getPrimaryTableAlias() {
+    return 'email';
+  }
+
+  protected function buildWhereClauseParts(AphrontDatabaseConnection $conn) {
+    $where = parent::buildWhereClauseParts($conn);
+
+    if ($this->ids !== null) {
+      $where[] = qsprintf(
+        $conn,
+        'email.id IN (%Ld)',
+        $this->ids);
+    }
+
+    if ($this->phids !== null) {
+      $where[] = qsprintf(
+        $conn,
+        'email.phid IN (%Ls)',
+        $this->phids);
+    }
+
+    return $where;
+  }
+
+  public function getQueryApplicationClass() {
+    return 'PhabricatorPeopleApplication';
+  }
+
+}

src/applications/people/storage/PhabricatorUserEmail.php

···
 
   protected function getConfiguration() {
     return array(
+      self::CONFIG_AUX_PHID => true,
       self::CONFIG_COLUMN_SCHEMA => array(
         'address' => 'sort128',
         'isVerified' => 'bool',
···
         ),
       ),
     ) + parent::getConfiguration();
+  }
+
+  public function getPHIDType() {
+    return PhabricatorPeopleUserEmailPHIDType::TYPECONST;
   }
 
   public function getVerificationURI() {