feature #19339 [WebProfilerBundle][Form][DX] To expand the form nodes that contains children with errors (yceruto)

This PR was squashed before being merged into the 3.2-dev branch (closes #19339).

Discussion
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[WebProfilerBundle][Form][DX] To expand the form nodes that contains children with errors

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

Currently when we use nested forms and an error occurs into one of them, it's not displayed "easily" in the form panel profiler:

![first](https://cloud.githubusercontent.com/assets/2028198/17125622/1fd15142-52c3-11e6-830e-17b3e341ba60.png)

This happen because only the root form is expanded and the children are shown collapsed "by default".

**The main problem is to search where is the form with error**.

The purpose of this PR is to show expanded all forms that contains children with error, reducing a little bit the developer's time when debugging.

PR result when we access to the form panel profiler:

![form-error-result](https://cloud.githubusercontent.com/assets/2028198/17125447/83eb9c0c-52c1-11e6-94bc-a2a7492eea43.png)

In red the full path to the error.

![form-error-result2](https://cloud.githubusercontent.com/assets/2028198/17125459/a04de95e-52c1-11e6-8980-84a5dcd0914a.png)

Commits
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d626b28 [WebProfilerBundle][Form][DX] To expand the form nodes that contains children with errors

Author: fabpot

Resources/views/Collector/form.html.twig

@@ -164,6 +164,9 @@
             font-weight: bold;
             vertical-align: middle;
         }
+        .has-error {
+            color: #B0413E;
+        }
         .errors h3 {
             color: #B0413E;
         }
@@ -423,11 +426,12 @@
     </script>
 {% endblock %}
 
-{% macro form_tree_entry(name, data, expanded) %}
+{% macro form_tree_entry(name, data, is_root) %}
     {% import _self as tree %}
+    {% set has_error = data.errors is defined and data.errors|length > 0 %}
     <li>
         <div class="tree-inner" data-tab-target-id="{{ data.id }}-details">
-            {% if data.errors is defined and data.errors|length > 0 %}
+            {% if has_error %}
                 <div class="badge-error">{{ data.errors|length }}</div>
             {% endif %}
 
@@ -437,11 +441,13 @@
                 <div class="toggle-icon empty"></div>
             {% endif %}
 
-            {{ name|default('(no name)') }} {% if data.type_class is defined %}[<abbr title="{{ data.type_class }}">{{ data.type_class|split('\\')|last }}</abbr>]{% endif %}
+            <span {% if has_error or data.has_children_error|default(false) %}class="has-error"{% endif %}>
+                {{ name|default('(no name)') }} {% if data.type_class is defined %}[<abbr title="{{ data.type_class }}">{{ data.type_class|split('\\')|last }}</abbr>]{% endif %}
+            </span>
         </div>
 
         {% if data.children is not empty %}
-            <ul id="{{ data.id }}-children" {% if not expanded %}class="hidden"{% endif %}>
+            <ul id="{{ data.id }}-children" {% if not is_root and not data.has_children_error|default(false) %}class="hidden"{% endif %}>
                 {% for childName, childData in data.children %}
                     {{ tree.form_tree_entry(childName, childData, false) }}
                 {% endfor %}