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/EnumOptions.php b/php/src/Google/Protobuf/Internal/EnumOptions.php
index 4fa0bce7..cfa0cb3e 100644
--- a/php/src/Google/Protobuf/Internal/EnumOptions.php
+++ b/php/src/Google/Protobuf/Internal/EnumOptions.php
@@ -79,6 +79,8 @@ class EnumOptions extends \Google\Protobuf\Internal\Message
         GPBUtil::checkBool($var);
         $this->allow_alias = $var;
         $this->has_allow_alias = true;
+
+        return $this;
     }
 
     public function hasAllowAlias()
@@ -116,6 +118,8 @@ class EnumOptions extends \Google\Protobuf\Internal\Message
         GPBUtil::checkBool($var);
         $this->deprecated = $var;
         $this->has_deprecated = true;
+
+        return $this;
     }
 
     public function hasDeprecated()
@@ -147,6 +151,8 @@ class EnumOptions extends \Google\Protobuf\Internal\Message
         $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\UninterpretedOption::class);
         $this->uninterpreted_option = $arr;
         $this->has_uninterpreted_option = true;
+
+        return $this;
     }
 
     public function hasUninterpretedOption()