Add new file option php_namespace. (#3162)

* Add new file option php_namespace.

Use this option to change the namespace of php generated classes.
Default is empty. When this option is empty, the package name will be
used for determining the namespace.

* Uncomment commented tests

* Revert gdb test change

* Update csharp descriptor.

* Add test for empty php_namespace.

1 files changed, 6 insertions, 0 deletions

diff --git a/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php b/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php
index 73f6edbd..bf597436 100644
--- a/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php
+++ b/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php
@@ -57,6 +57,8 @@ class EnumDescriptorProto extends \Google\Protobuf\Internal\Message
         GPBUtil::checkString($var, True);
         $this->name = $var;
         $this->has_name = true;
+
+        return $this;
     }
 
     public function hasName()
@@ -80,6 +82,8 @@ class EnumDescriptorProto extends \Google\Protobuf\Internal\Message
         $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\EnumValueDescriptorProto::class);
         $this->value = $arr;
         $this->has_value = true;
+
+        return $this;
     }
 
     public function hasValue()
@@ -103,6 +107,8 @@ class EnumDescriptorProto extends \Google\Protobuf\Internal\Message
         GPBUtil::checkMessage($var, \Google\Protobuf\Internal\EnumOptions::class);
         $this->options = $var;
         $this->has_options = true;
+
+        return $this;
     }
 
     public function hasOptions()