bug #105 register FormDataCollector with container to make it singleton (sarim)
bug #105 register FormDataCollector with container to make it singleton (sarim)

This PR was merged into the 2.0.x-dev branch.

Discussion
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register FormDataCollector with container to make it singleton

The issue is the form section of webprofiler is always empty. This is because one instance of `FormDataCollector` collects form information via form events, but when webprofiler is rendered, it gets a another newly instantiated `FormDataCollector` which is obviously empty.

My solution registers `FormDataCollector` as a service to $app and returns it. This way single instance of `FormDataCollector` collects form data then webprofiler gets that same instance, so it can show form information.

Commits
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b369942 register FormDataCollector with container to make it singleton

silexphp/Silex-WebProfiler,augustinmerle/Silex-WebProfiler