[Request] Support ComWrappers API in debug interfaces for diagnostic CCW/RCW decoding.

[chuckries]

The VS Debugger has the ability to decode CCW's and RCW's while mixed mode debugging in order to visualize a managed object through a native interface pointer and vice versa. If a customer begins to consume the new ComWrappers API, this decoding will stop working. In .NET 6, the necessary debug interface implementations should be updated to work with ComWrappers API.

VS's CCW and RCW is primarily focused on supporting internal devs, even though it is publicly available. This is not being driven by a customer ask.

APIs

CCW Decoding

ICorDebugAppDomain4::GetObjectForCCW

RCW Decoding

Today the debugger uses ICorDebugComObjectValue::GetCachedInterfacePointers to obtain the IUnknown* for a managed object. As this interface can't be fully supported by ComWrappers API, I suggest we add a new API such as ICorDeubgComObjectValue2::GetIUnknown().

[ghost]

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[chuckries]

cc @AaronRobinsonMSFT @tommcdon

[chuckries]

The primary driver of this is to support CsWinRt scenarios.

[AaronRobinsonMSFT]

/cc @Scottj1s @davmason