[WebProfilerBundle] Fixed double height of canvas
return empty metadata collection if none do exist

The PropertyMetadataContainerInterface defines that the method
getPropertyMetadata() has to return an empty collection if no
metadata have been configured for the given property. Though, its
implementation in the ClassMetadata class didn't check for
existence of such metadata. This behavior led to unexpected PHP
notices when validating a property or a property value of a property
without any configured constraints (only affects the new 2.5 API).
Additionally, the getMemberMetadatas() didn't check for existing
array keys as well which has also been fixed.
revert #11510, moved to 2.6
bug #11529 [WebProfilerBundle] Fixed double height of canvas (hason)

This PR was merged into the 2.3 branch.

Discussion
----------

[WebProfilerBundle] Fixed double height of canvas

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7065
| License       | MIT
| Doc PR        | -

Commits
-------

c689186 [WebProfilerBundle] Fixed double height of canvas
minor #11667 [HttpFoundation] revert #11510, moved to 2.6 (nicolas-grekas)

This PR was merged into the 2.3 branch.

Discussion
----------

[HttpFoundation] revert #11510, moved to 2.6

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | none
| License       | MIT
| Doc PR        | none

This reverts PR #11510 from 2.3.

Commits
-------

fb120c7 revert #11510, moved to 2.6
[FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9
[Form] Fixed ValidatorExtension to work with the 2.5 Validation API
bug #11645 [Form] Fixed ValidatorExtension to work with the 2.5 Validation API (webmozart)

This PR was merged into the 2.5 branch.

Discussion
----------

[Form] Fixed ValidatorExtension to work with the 2.5 Validation API

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11606
| License       | MIT
| Doc PR        | -

The ValidatorExtension::loadTypeGuesser() method used to fail because the method `getMetadataFactory()` does not exist anymore on the new `ValidatorInterface`. This was fixed easily, because `ValidatorInterface` now extends `ClassMetadataFactory`.

Commits
-------

ff74f4e [Form] Fixed ValidatorExtension to work with the 2.5 Validation API
add missing options
minor #11674 [Validator] Add missing translation NL (1emming)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #11674).

Discussion
----------

[Validator] Add missing translation NL

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | part of #11489
| License       | MIT

Commits
-------

2d5ab91 add missing options
Merge branch '2.3' into 2.4

* 2.3:
  add missing options
  revert #11510, moved to 2.6
  [WebProfilerBundle] Fixed double height of canvas
Merge branch '2.4' into 2.5

* 2.4:
  add missing options
  revert #11510, moved to 2.6
  [WebProfilerBundle] Fixed double height of canvas
Merge branch '2.5'

* 2.5:
  add missing options
  [Form] Fixed ValidatorExtension to work with the 2.5 Validation API
  revert #11510, moved to 2.6
  [WebProfilerBundle] Fixed double height of canvas
[HttpFoundation] MongoDbSessionHandler supports auto expiry via configurable expiry_field
feature #11668 [HttpFoundation] MongoDbSessionHandler supports auto expiry via configurable expiry_field (catchamonkey)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[HttpFoundation] MongoDbSessionHandler supports auto expiry via configurable expiry_field

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11508
| License       | MIT
| Doc PR        | no

This PR applies #11510 to master instead of 2.3

Should be merged on master:
- [x] after https://github.com/symfony/symfony/pull/11667 is merged to 2.3
- [x] and after 2.3 is merged back to master

Commits
-------

beca900 [HttpFoundation] MongoDbSessionHandler supports auto expiry via configurable expiry_field
[Validator] Fixed Constraint class to not destroy custom groups upon serialization
bug #11584 [FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9 (webmozart)

This PR was merged into the 2.5 branch.

Discussion
----------

[FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11580
| License       | MIT
| Doc PR        | -

Commits
-------

a74b758 [FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9
bug #11691 [Validator] Fixed Constraint class to not destroy custom groups upon serialization (webmozart)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[Validator] Fixed Constraint class to not destroy custom groups upon serialization

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11638
| License       | MIT
| Doc PR        | -

Commits
-------

d405f43 [Validator] Fixed Constraint class to not destroy custom groups upon serialization
minor #11615 [Validator] return empty metadata collection if none do exist (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Validator] return empty metadata collection if none do exist

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        | [The reference to the documentation PR if any]

Backport of #11614 for Symfony 2.3 and 2.4.

Commits
-------

f5bc18d return empty metadata collection if none do exist
[Validators] Fixed failing tests requiring ICU 52.1 which are skipped otherwise