Revamp input source management

[svillar]

The input source management was not correct. There were some bugs in the current implementation and there are also some missing very important features.

This PR implements the following:

• Use the XrStandardGamepadBuilder to create the Gamepad object. This ensures that is created with the xr-standard mapping required by the WebXR implementation. Also it simplifies a bit the code.
• Properly fill in the primaryinput and primarysqueeze data. Those 4 values are defined in the WebXR spec (primary action and primary squeeze action) and are used to properly trigger the select and squeeze events. This requires storing the previous state of the controllers.
• Fix touchpad and thumbstick support. There was no touchpad support at all. Also axes values were not properly filled in. Last but not least, thumbstick's click/touch/value were not filled in.

Note: the index for where the data for a particular button is located follows the xr-standard gamepad mapping that can be found https://www.w3.org/TR/webxr-gamepads-module-1/#xr-standard-gamepad-mapping

[svillar]

There are a few good resources where to test these changes:

• controller state: useful to check that the value of all buttons is properly set. Pay special attention to thumbstick, rotate it, touch and also click on it.
• teleportation: several issues with original code, the user was teleported without touching any button, just pointing the controller down. Also clicking on the 3 squares did not have the desired effect.
• castle builder: elements of the castle can now be drag&dropped

[tiagovignatti]

We need to get the input state class split out of WvmManager. See https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/vr/input_delegate.h as a reference, specially the classes extending it. Do you mind looking into that @svillar, given that you're revamping the input source management? Thank you very much.

[svillar]

We need to get the input state class split out of WvmManager. See https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/vr/input_delegate.h as a reference, specially the classes extending it. Do you mind looking into that @svillar, given that you're revamping the input source management? Thank you very much.

Would you mind if we do that in a follow-up? I think it's a good idea to have first the correct implementation with the current structure, and then we could refactor it. Doing both things at once could complicate future rebases/blames/etc...