diff --git a/Dialogflow/metadata/V2/Agent.php b/Dialogflow/metadata/V2/Agent.php
index 32a1d6602e0b..e4883ad04b35 100644
--- a/Dialogflow/metadata/V2/Agent.php
+++ b/Dialogflow/metadata/V2/Agent.php
@@ -94,7 +94,7 @@ public static function initOnce() {
             "75642f6469616c6f67666c6f772f76323b6469616c6f67666c6f77f80101" .
             "a202024446aa021a476f6f676c652e436c6f75642e4469616c6f67666c6f" .
             "772e5632620670726f746f33"
-        ));
+        ), true);
 
         static::$is_initialized = true;
     }
diff --git a/Dialogflow/metadata/V2/Context.php b/Dialogflow/metadata/V2/Context.php
index a705f2073d0a..389b24ae5ea7 100644
--- a/Dialogflow/metadata/V2/Context.php
+++ b/Dialogflow/metadata/V2/Context.php
@@ -85,7 +85,7 @@ public static function initOnce() {
             "6c6f67666c6f772f76323b6469616c6f67666c6f77f80101a202024446aa" .
             "021a476f6f676c652e436c6f75642e4469616c6f67666c6f772e56326206" .
             "70726f746f33"
-        ));
+        ), true);
 
         static::$is_initialized = true;
     }
diff --git a/Dialogflow/metadata/V2/EntityType.php b/Dialogflow/metadata/V2/EntityType.php
index 4b086ff98c30..36fe99276c06 100644
--- a/Dialogflow/metadata/V2/EntityType.php
+++ b/Dialogflow/metadata/V2/EntityType.php
@@ -159,7 +159,7 @@ public static function initOnce() {
             "69732f636c6f75642f6469616c6f67666c6f772f76323b6469616c6f6766" .
             "6c6f77f80101a202024446aa021a476f6f676c652e436c6f75642e446961" .
             "6c6f67666c6f772e5632620670726f746f33"
-        ));
+        ), true);
 
         static::$is_initialized = true;
     }
diff --git a/Dialogflow/metadata/V2/Intent.php b/Dialogflow/metadata/V2/Intent.php
index 81e9a5ae97bc..5073380f0899 100644
--- a/Dialogflow/metadata/V2/Intent.php
+++ b/Dialogflow/metadata/V2/Intent.php
@@ -260,7 +260,7 @@ public static function initOnce() {
             "2f6469616c6f67666c6f772f76323b6469616c6f67666c6f77f80101a202" .
             "024446aa021a476f6f676c652e436c6f75642e4469616c6f67666c6f772e" .
             "5632620670726f746f33"
-        ));
+        ), true);
 
         static::$is_initialized = true;
     }
diff --git a/Dialogflow/metadata/V2/Session.php b/Dialogflow/metadata/V2/Session.php
index e95ac8c6d789..47eb9ed1764a 100644
--- a/Dialogflow/metadata/V2/Session.php
+++ b/Dialogflow/metadata/V2/Session.php
@@ -139,7 +139,7 @@ public static function initOnce() {
             "617069732f636c6f75642f6469616c6f67666c6f772f76323b6469616c6f" .
             "67666c6f77f80101a202024446aa021a476f6f676c652e436c6f75642e44" .
             "69616c6f67666c6f772e5632620670726f746f33"
-        ));
+        ), true);
 
         static::$is_initialized = true;
     }
diff --git a/Dialogflow/metadata/V2/SessionEntityType.php b/Dialogflow/metadata/V2/SessionEntityType.php
index b59696f173f6..7560f404a26b 100644
--- a/Dialogflow/metadata/V2/SessionEntityType.php
+++ b/Dialogflow/metadata/V2/SessionEntityType.php
@@ -98,7 +98,7 @@ public static function initOnce() {
             "2f636c6f75642f6469616c6f67666c6f772f76323b6469616c6f67666c6f" .
             "77f80101a202024446aa021a476f6f676c652e436c6f75642e4469616c6f" .
             "67666c6f772e5632620670726f746f33"
-        ));
+        ), true);
 
         static::$is_initialized = true;
     }
diff --git a/Dialogflow/metadata/V2/Webhook.php b/Dialogflow/metadata/V2/Webhook.php
index 669500ca8f9f..919a7b6d332d 100644
--- a/Dialogflow/metadata/V2/Webhook.php
+++ b/Dialogflow/metadata/V2/Webhook.php
@@ -54,7 +54,7 @@ public static function initOnce() {
             "617069732f636c6f75642f6469616c6f67666c6f772f76323b6469616c6f" .
             "67666c6f77f80101a202024446aa021a476f6f676c652e436c6f75642e44" .
             "69616c6f67666c6f772e5632620670726f746f33"
-        ));
+        ), true);
 
         static::$is_initialized = true;
     }
diff --git a/Dialogflow/src/V2/Agent/MatchMode.php b/Dialogflow/src/V2/Agent/MatchMode.php
index 11c4be8ee583..1e30c2c3c2bf 100644
--- a/Dialogflow/src/V2/Agent/MatchMode.php
+++ b/Dialogflow/src/V2/Agent/MatchMode.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\Agent;
 
+use UnexpectedValueException;
+
 /**
  * Match mode determines how intents are detected from user queries.
  *
@@ -31,6 +33,32 @@ class MatchMode
      * Generated from protobuf enum <code>MATCH_MODE_ML_ONLY = 2;</code>
      */
     const MATCH_MODE_ML_ONLY = 2;
+
+    private static $valueToName = [
+        self::MATCH_MODE_UNSPECIFIED => 'MATCH_MODE_UNSPECIFIED',
+        self::MATCH_MODE_HYBRID => 'MATCH_MODE_HYBRID',
+        self::MATCH_MODE_ML_ONLY => 'MATCH_MODE_ML_ONLY',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/src/V2/AudioEncoding.php b/Dialogflow/src/V2/AudioEncoding.php
index de817a1f20a6..1329f523f94f 100644
--- a/Dialogflow/src/V2/AudioEncoding.php
+++ b/Dialogflow/src/V2/AudioEncoding.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2;
 
+use UnexpectedValueException;
+
 /**
  * Audio encoding of the audio content sent in the conversational query request.
  * Refer to the [Cloud Speech API documentation](/speech/docs/basics) for more
@@ -79,5 +81,36 @@ class AudioEncoding
      * Generated from protobuf enum <code>AUDIO_ENCODING_SPEEX_WITH_HEADER_BYTE = 7;</code>
      */
     const AUDIO_ENCODING_SPEEX_WITH_HEADER_BYTE = 7;
+
+    private static $valueToName = [
+        self::AUDIO_ENCODING_UNSPECIFIED => 'AUDIO_ENCODING_UNSPECIFIED',
+        self::AUDIO_ENCODING_LINEAR_16 => 'AUDIO_ENCODING_LINEAR_16',
+        self::AUDIO_ENCODING_FLAC => 'AUDIO_ENCODING_FLAC',
+        self::AUDIO_ENCODING_MULAW => 'AUDIO_ENCODING_MULAW',
+        self::AUDIO_ENCODING_AMR => 'AUDIO_ENCODING_AMR',
+        self::AUDIO_ENCODING_AMR_WB => 'AUDIO_ENCODING_AMR_WB',
+        self::AUDIO_ENCODING_OGG_OPUS => 'AUDIO_ENCODING_OGG_OPUS',
+        self::AUDIO_ENCODING_SPEEX_WITH_HEADER_BYTE => 'AUDIO_ENCODING_SPEEX_WITH_HEADER_BYTE',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
diff --git a/Dialogflow/src/V2/EntityType/AutoExpansionMode.php b/Dialogflow/src/V2/EntityType/AutoExpansionMode.php
index 39ada3360492..77ac68085257 100644
--- a/Dialogflow/src/V2/EntityType/AutoExpansionMode.php
+++ b/Dialogflow/src/V2/EntityType/AutoExpansionMode.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\EntityType;
 
+use UnexpectedValueException;
+
 /**
  * Represents different entity type expansion modes. Automated expansion
  * allows an agent to recognize values that have not been explicitly listed in
@@ -26,6 +28,31 @@ class AutoExpansionMode
      * Generated from protobuf enum <code>AUTO_EXPANSION_MODE_DEFAULT = 1;</code>
      */
     const AUTO_EXPANSION_MODE_DEFAULT = 1;
+
+    private static $valueToName = [
+        self::AUTO_EXPANSION_MODE_UNSPECIFIED => 'AUTO_EXPANSION_MODE_UNSPECIFIED',
+        self::AUTO_EXPANSION_MODE_DEFAULT => 'AUTO_EXPANSION_MODE_DEFAULT',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/src/V2/EntityType/Kind.php b/Dialogflow/src/V2/EntityType/Kind.php
index c35e6a189516..66b7261a3796 100644
--- a/Dialogflow/src/V2/EntityType/Kind.php
+++ b/Dialogflow/src/V2/EntityType/Kind.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\EntityType;
 
+use UnexpectedValueException;
+
 /**
  * Represents kinds of entities.
  *
@@ -32,6 +34,32 @@ class Kind
      * Generated from protobuf enum <code>KIND_LIST = 2;</code>
      */
     const KIND_LIST = 2;
+
+    private static $valueToName = [
+        self::KIND_UNSPECIFIED => 'KIND_UNSPECIFIED',
+        self::KIND_MAP => 'KIND_MAP',
+        self::KIND_LIST => 'KIND_LIST',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/src/V2/Intent/Message/Platform.php b/Dialogflow/src/V2/Intent/Message/Platform.php
index 5076d01a626f..003d85d30c88 100644
--- a/Dialogflow/src/V2/Intent/Message/Platform.php
+++ b/Dialogflow/src/V2/Intent/Message/Platform.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\Intent\Message;
 
+use UnexpectedValueException;
+
 /**
  * Represents different platforms that a rich message can be intended for.
  *
@@ -125,6 +127,38 @@ class Platform
      * Generated from protobuf enum <code>ACTIONS_ON_GOOGLE = 8;</code>
      */
     const ACTIONS_ON_GOOGLE = 8;
+
+    private static $valueToName = [
+        self::PLATFORM_UNSPECIFIED => 'PLATFORM_UNSPECIFIED',
+        self::FACEBOOK => 'FACEBOOK',
+        self::SLACK => 'SLACK',
+        self::TELEGRAM => 'TELEGRAM',
+        self::KIK => 'KIK',
+        self::SKYPE => 'SKYPE',
+        self::LINE => 'LINE',
+        self::VIBER => 'VIBER',
+        self::ACTIONS_ON_GOOGLE => 'ACTIONS_ON_GOOGLE',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/src/V2/Intent/TrainingPhrase/Type.php b/Dialogflow/src/V2/Intent/TrainingPhrase/Type.php
index d530b5e021f5..85578c2ff950 100644
--- a/Dialogflow/src/V2/Intent/TrainingPhrase/Type.php
+++ b/Dialogflow/src/V2/Intent/TrainingPhrase/Type.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\Intent\TrainingPhrase;
 
+use UnexpectedValueException;
+
 /**
  * Represents different types of training phrases.
  *
@@ -31,6 +33,32 @@ class Type
      * Generated from protobuf enum <code>TEMPLATE = 2;</code>
      */
     const TEMPLATE = 2;
+
+    private static $valueToName = [
+        self::TYPE_UNSPECIFIED => 'TYPE_UNSPECIFIED',
+        self::EXAMPLE => 'EXAMPLE',
+        self::TEMPLATE => 'TEMPLATE',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/src/V2/Intent/WebhookState.php b/Dialogflow/src/V2/Intent/WebhookState.php
index ad804207b6ba..7282b5d28d99 100644
--- a/Dialogflow/src/V2/Intent/WebhookState.php
+++ b/Dialogflow/src/V2/Intent/WebhookState.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\Intent;
 
+use UnexpectedValueException;
+
 /**
  * Represents the different states that webhooks can be in.
  *
@@ -30,6 +32,32 @@ class WebhookState
      * Generated from protobuf enum <code>WEBHOOK_STATE_ENABLED_FOR_SLOT_FILLING = 2;</code>
      */
     const WEBHOOK_STATE_ENABLED_FOR_SLOT_FILLING = 2;
+
+    private static $valueToName = [
+        self::WEBHOOK_STATE_UNSPECIFIED => 'WEBHOOK_STATE_UNSPECIFIED',
+        self::WEBHOOK_STATE_ENABLED => 'WEBHOOK_STATE_ENABLED',
+        self::WEBHOOK_STATE_ENABLED_FOR_SLOT_FILLING => 'WEBHOOK_STATE_ENABLED_FOR_SLOT_FILLING',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/src/V2/IntentView.php b/Dialogflow/src/V2/IntentView.php
index e5c15f114be4..916e50e6b7db 100644
--- a/Dialogflow/src/V2/IntentView.php
+++ b/Dialogflow/src/V2/IntentView.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2;
 
+use UnexpectedValueException;
+
 /**
  * Represents the options for views of an intent.
  * An intent can be a sizable object. Therefore, we provide a resource view that
@@ -25,5 +27,30 @@ class IntentView
      * Generated from protobuf enum <code>INTENT_VIEW_FULL = 1;</code>
      */
     const INTENT_VIEW_FULL = 1;
+
+    private static $valueToName = [
+        self::INTENT_VIEW_UNSPECIFIED => 'INTENT_VIEW_UNSPECIFIED',
+        self::INTENT_VIEW_FULL => 'INTENT_VIEW_FULL',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
diff --git a/Dialogflow/src/V2/SessionEntityType/EntityOverrideMode.php b/Dialogflow/src/V2/SessionEntityType/EntityOverrideMode.php
index af553004ed2b..af5a026dbdda 100644
--- a/Dialogflow/src/V2/SessionEntityType/EntityOverrideMode.php
+++ b/Dialogflow/src/V2/SessionEntityType/EntityOverrideMode.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\SessionEntityType;
 
+use UnexpectedValueException;
+
 /**
  * The types of modifications for a session entity type.
  *
@@ -35,6 +37,32 @@ class EntityOverrideMode
      * Generated from protobuf enum <code>ENTITY_OVERRIDE_MODE_SUPPLEMENT = 2;</code>
      */
     const ENTITY_OVERRIDE_MODE_SUPPLEMENT = 2;
+
+    private static $valueToName = [
+        self::ENTITY_OVERRIDE_MODE_UNSPECIFIED => 'ENTITY_OVERRIDE_MODE_UNSPECIFIED',
+        self::ENTITY_OVERRIDE_MODE_OVERRIDE => 'ENTITY_OVERRIDE_MODE_OVERRIDE',
+        self::ENTITY_OVERRIDE_MODE_SUPPLEMENT => 'ENTITY_OVERRIDE_MODE_SUPPLEMENT',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/src/V2/StreamingRecognitionResult/MessageType.php b/Dialogflow/src/V2/StreamingRecognitionResult/MessageType.php
index 1e48b773d846..91db6b179001 100644
--- a/Dialogflow/src/V2/StreamingRecognitionResult/MessageType.php
+++ b/Dialogflow/src/V2/StreamingRecognitionResult/MessageType.php
@@ -4,6 +4,8 @@
 
 namespace Google\Cloud\Dialogflow\V2\StreamingRecognitionResult;
 
+use UnexpectedValueException;
+
 /**
  * Type of the response message.
  *
@@ -35,6 +37,32 @@ class MessageType
      * Generated from protobuf enum <code>END_OF_SINGLE_UTTERANCE = 2;</code>
      */
     const END_OF_SINGLE_UTTERANCE = 2;
+
+    private static $valueToName = [
+        self::MESSAGE_TYPE_UNSPECIFIED => 'MESSAGE_TYPE_UNSPECIFIED',
+        self::TRANSCRIPT => 'TRANSCRIPT',
+        self::END_OF_SINGLE_UTTERANCE => 'END_OF_SINGLE_UTTERANCE',
+    ];
+
+    public static function name($value)
+    {
+        if (!isset(self::$valueToName[$value])) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no name defined for value %s', __CLASS__, $value));
+        }
+        return self::$valueToName[$value];
+    }
+
+
+    public static function value($name)
+    {
+        $const = __CLASS__ . '::' . strtoupper($name);
+        if (!defined($const)) {
+            throw new UnexpectedValueException(sprintf(
+                    'Enum %s has no value defined for name %s', __CLASS__, $name));
+        }
+        return constant($const);
+    }
 }
 
 // Adding a class alias for backwards compatibility with the previous class name.
diff --git a/Dialogflow/synth.metadata b/Dialogflow/synth.metadata
index f64db519b816..24e496bd2929 100644
--- a/Dialogflow/synth.metadata
+++ b/Dialogflow/synth.metadata
@@ -1,19 +1,19 @@
 {
-  "updateTime": "2019-03-28T10:00:21.107191Z",
+  "updateTime": "2019-03-29T10:00:11.614693Z",
   "sources": [
     {
       "generator": {
         "name": "artman",
-        "version": "0.16.20",
-        "dockerImage": "googleapis/artman@sha256:e3c054a2fb85a12481c722af616c7fb6f1d02d862248385eecbec3e4240ebd1e"
+        "version": "0.16.21",
+        "dockerImage": "googleapis/artman@sha256:854131ec1af7b3a313253474c24748dc0acd217a58a0b74dbfb559f340a15d78"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "6a84b3267b0a95e922608b9891219075047eee29",
-        "internalRef": "240640999"
+        "sha": "37386f1ebcaed51bcb7d15d00124d22c38606e45",
+        "internalRef": "240841842"
       }
     }
   ],