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, 10 insertions, 0 deletions

diff --git a/php/src/Google/Protobuf/Internal/MessageOptions.php b/php/src/Google/Protobuf/Internal/MessageOptions.php
index 747f3294..a5835358 100644
--- a/php/src/Google/Protobuf/Internal/MessageOptions.php
+++ b/php/src/Google/Protobuf/Internal/MessageOptions.php
@@ -155,6 +155,8 @@ class MessageOptions extends \Google\Protobuf\Internal\Message
         GPBUtil::checkBool($var);
         $this->message_set_wire_format = $var;
         $this->has_message_set_wire_format = true;
+
+        return $this;
     }
 
     public function hasMessageSetWireFormat()
@@ -190,6 +192,8 @@ class MessageOptions extends \Google\Protobuf\Internal\Message
         GPBUtil::checkBool($var);
         $this->no_standard_descriptor_accessor = $var;
         $this->has_no_standard_descriptor_accessor = true;
+
+        return $this;
     }
 
     public function hasNoStandardDescriptorAccessor()
@@ -227,6 +231,8 @@ class MessageOptions extends \Google\Protobuf\Internal\Message
         GPBUtil::checkBool($var);
         $this->deprecated = $var;
         $this->has_deprecated = true;
+
+        return $this;
     }
 
     public function hasDeprecated()
@@ -292,6 +298,8 @@ class MessageOptions extends \Google\Protobuf\Internal\Message
         GPBUtil::checkBool($var);
         $this->map_entry = $var;
         $this->has_map_entry = true;
+
+        return $this;
     }
 
     public function hasMapEntry()
@@ -323,6 +331,8 @@ class MessageOptions 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()