Merge branch '6.1' into 6.2

* 6.1:
  [FrameworkBundle][HttpKernel] Document `collect_parameter`

Author: javiereguiluz

reference/configuration/framework.rst

@@ -1264,6 +1264,22 @@ activate the data collectors manually::
 
     $profiler->enable();
 
+collect_parameter
+.................
+
+**type**: ``string`` **default**: ``null``
+
+This specifies name of a query parameter, a body parameter or a request attribute
+used to enable or disable collection of data by the profiler for each request.
+Combine it with the ``collect`` option to enable/disable the profiler on demand:
+
+* If the ``collect`` option is set to ``true`` but this parameter exists in a
+  request and has any value other than ``true``, ``yes``, ``on`` or ``1``, the
+  request data will not be collected;
+* If the ``collect`` option is set to ``false``, but this parameter exists in a
+  request and has value of ``true``, ``yes``, ``on`` or ``1``, the request data
+  will be collected.
+
 only_exceptions
 ...............