Add an inspector page

[jacob314]

Match functionality of intellij inspector. Write code so it is straightforward to port to Hummingbird.

[devoncarew]

I think we can host this in the Device page, or move the (currently minimal) contents of the device page into an Inspector page.

[jacob314]

I like it. The existing Device icon works better for the inspector than the ugly hour glass I had been using.

[rrousselGit]

👋 (not sure if this is fine to ask it here, but I don't see any other location, and this is related)

I'm working on integrating a new kind of widgets with the widget inspector. And I've been wondering a few things about how the style of a Diagnosticable node is rendered:

• What determines if a node should have an icon or not?
• How is that icon picked? Some widgets seem to have a custom icon (animated widgets, which have a play button).
• What makes the name of a node bold?
• Why does sometimes a property can be expended and sometimes not? For example on the previous screen capture, renderObject have nested fields. But if we added a renderObject within that renderObject, the nested one would be printed as toString.

Also:
Will this tool have the exact same rendering as found in IntelliJ, or is it possible that there will be some differences?

Sorry for the inconvenience and thanks in advance!

[jacob314]

Answers:

1. https://github.com/flutter/devtools/blob/master/packages/devtools/lib/src/inspector/flutter_widget.dart
   loads the json defining the categories for widgets and defines the icon mapping. We could do more to polish the icons and the mapping and allow users to provide annotations on their widget classes so user widgets are categorized as well.
2. Bold nodes are widgets created by the local project. This is done by running with the --track-widget-creation flag to figure out which widgets are local.
3. Actually that sounds like a bug and you should see all properties where the value implements Diagnosticable be expandable in the web based devtools app.

The rendering is quite consistent but we may add features in one place (typically Devtools) before adding back to Intellij.